“We have one set of laws in this country and they apply to everyone,” he said. The investigation was being conducted with utmost integrity, he added, and promised to seek a speedy trial. He did not take questions.

The indictment gives the clearest picture yet of the files that Mr. Trump took with him when he left the White House. It said he had illegally kept hold of documents concerning “United States nuclear programs; potential vulnerabilities of the United States and its allies to military attack; and plans for possible retaliation in response to a foreign attack.”

The indictment names one of his personal aides, Walt Nauta, as a co-conspirator who assisted in obstructing the investigation into the former president’s retention of sensitive defense documents at his residence and resort in Florida.

Prosecutors presented evidence that Mr. Trump shared a highly sensitive “plan of attack” against Iran to visitors at his golf club in Bedminster, N.J., in July 2021 — and was recorded on tape describing the material as “highly confidential” and “secret,” while admitting it had not been declassified.

In another incident in September 2021, he shared a top secret military map with a staffer at his political action committee who did not have a security clearance.

The filing includes many pictures of what appear to be bankers’ boxes, some containing highly sensitive national documents, which were haphazardly moved by Mr. Nauta and other aides at Mr. Trump’s behest. Some of the boxes appear to be sagging — and on Dec. 7, 2021, Mr. Nauta found that one of the boxes had toppled and spilled its contents on the floor.

The files that splayed on the carpet included the designation “SECRET/REL TO USA, FVEY” — which meant that they were meant to be seen by officials from the U.S., Britain, New Zealand, Australia and Canada with high-level security clearances.

Mr. Trump is expected to appear in Federal District Court in Miami on Tuesday afternoon. Judge Aileen M. Cannon is scheduled to preside over that initial hearing, according to people familiar with the matter. It was not clear whether Judge Cannon, who was criticized by a higher court for handing Mr. Trump a series of unusually favorable rulings during the early stages of the investigation, would remain assigned for the entirety of the case.

The indictment, handed up by a grand jury in Miami, is the first time a former president has faced federal charges. It puts the nation in an extraordinary position, given Mr. Trump’s status not only as a onetime commander in chief but also as the current front-runner for the 2024 Republican presidential nomination to face President Biden, whose administration will now be seeking to convict his potential rival of multiple felonies.

Mr. Trump continued to rail against the indictment on Friday, calling it the “greatest witch hunt of all time,” in a Truth Social post.

Here’s what else to know:

• The indictment reaches back to the end of Mr. Trump’s term in January 2021, when the documents — many of which were said to be in the White House residence — were packed in boxes along with clothes, gifts, photographs and other material, and shipped by the General Services Administration to his private club and residence in Florida, Mar-a-Lago.

• Two lawyers, James Trusty and John Rowley, have left Mr. Trump’s legal team, and will no longer represent him in the documents case. “I will be represented by Todd Blanche, Esq., and a firm to be named later,” Mr. Trump wrote on Truth Social.

• A recording of a meeting involving Mr. Trump in July 2021, six months after leaving the White House, is expected to be a key piece of evidence against him. During that meeting, he described a document in front of him as “classified” and “highly confidential,” according to a person briefed on the matter.

Charlie Savage and Nicholas Nehamas contributed reporting.

The indictment would divide the nation, he said, but Mr. Trump had brought that on himself with poor conduct that “was completely self-inflicted.”

Mr. Christie said he still believes Hillary Clinton should have faced charges in response to her mishandling of classified documents on a private email server, and still does not believe the Trump campaign colluded with Russia in the 2016 election.

But, he added, “Each case needs to be assessed on its own merits, and the facts that are laid out here are damning.”

The prosecution of Mr. Trump is about “holding to account people who are in positions of responsibility,” he said.

Mr. Christie, who opened the broadcast by noting his own record as a federal prosecutor, has made his willingness to draw critical attention to Mr. Trump central to his campaign for the Republican presidential nomination in 2024. But only he and one other candidate, Asa Hutchinson, the former governor of Arkansas, spoke favorably on Friday of the government’s case against the former president.

The other candidates, balancing their need to curry favor with Mr. Trump’s supporters against the imperative to dislodge him as the front-runner, have largely taken the side of the Republican base, which sides with the former president.

Rather than saying the Justice Department is holding Mr. Trump to an unfair standard, Mr. Christie said a man of Mr. Trump’s stature and ambitions should be held to a higher standard.

“The conduct is bad,” he said of actions described in the indictment. “And it is bad for anybody in this country to do it, but it’s particularly awful for someone who has been president and who aspires to be president again.”

In an address to Republicans in North Carolina on Friday night, his first public remarks since the unsealing of federal charges against former President Donald J. Trump, Mr. DeSantis trod carefully and danced quickly past the subject.

Previewing how he might criticize the Justice Department’s case without letting Mr. Trump entirely off the hook, he offered a somewhat backhanded defense of the now twice-indicted former president — whose loyal followers Mr. DeSantis is seeking to avoid angering — by drawing on his own experiences as a Navy lawyer.

Seeming to muse aloud, Mr. DeSantis asked what the Navy would have done to him had he taken classified documents while in military service. “I would have been court-martialed in a New York minute,” he said, in a riff on Mr. Trump’s hometown.

While Mr. DeSantis made his remark in reference to the fact that Hillary Clinton did not face charges over her use of a private email server while she was secretary of state, his comments could just as easily have applied to Mr. Trump. And they suggested that he believed both Mr. Trump and Mrs. Clinton should have faced charges — or neither.

“Is there a different standard for a Democrat secretary of state versus a former Republican president?” he asked. “I think there needs to be one standard of justice in this country. Let’s enforce it on everybody and make sure we all know the rules.”

(A yearslong inquiry by the State Department found that Mrs. Clinton had not deliberately or systemically mishandled classified information.)

The nature of Mr. Trump’s federal indictment, which emerged in full view on Friday, left Mr. DeSantis and several other Republican presidential contenders ever more wobbly on the tightrope they are walking, trying to defend a rival accused of cavalierly and illegally keeping sensitive documents about U.S. nuclear programs and the country’s vulnerabilities to military attack.

Many of these candidates now find themselves in the difficult position of rallying around Mr. Trump even as they seek to differentiate themselves from his legacy while he continues to dominate them in the polls.

“This is not how justice should be pursued in our country,” Nikki Haley, the former governor of South Carolina and Mr. Trump’s United Nations ambassador, said on Twitter. “The American people are exhausted by the prosecutorial overreach, double standards and vendetta politics.”

Such caution struck a sharp contrast with the two Republican candidates most willing to criticize Mr. Trump.

Former Gov. Chris Christie of New Jersey called the indictment “devastating,” telling CNN that “the facts that are laid out here are damning.” And in an interview with The New York Times, former Gov. Asa Hutchinson of Arkansas pushed back against claims that Mr. Trump was being treated unfairly and reiterated his belief that he should drop out of the race.

“To pejoratively say this is the result of a political prosecution is not in service to our justice system,” Mr. Hutchinson said, adding, “It would be doing a disservice to the country if we did not treat this case seriously.”

Jack Smith, the special counsel leading the investigation, urged the public on Friday to understand the “scope and gravity” of the charges.

Mr. Trump is expected to appear in Federal District Court in Miami on Tuesday afternoon to face charges including willfully retaining national defense secrets in violation of the Espionage Act, making false statements and conspiracy to obstruct justice. On his Truth Social website, the former president called Mr. Smith “deranged.”

Some voters who attended Mr. DeSantis’s speech in Greensboro, N.C., suggested they were growing weary of the controversy surrounding Mr. Trump, even as they expressed a belief that the charges were politically motivated. (Mr. Trump also faces charges in state court in New York for his alleged role in paying hush money to a porn star.)

“Even if he gets elected again, they’re never going to leave him alone. So what’s the point?” said Mary Noble, 70, who voted twice for Mr. Trump but has not made up her mind in the 2024 primary. “He’ll never be effective. That’s my fear.”

Tom Wassel, who sells air pollution control equipment and also supported Mr. Trump in both previous elections, did not mind that Mr. DeSantis had touched on the indictment only briefly, and not very forcefully.

“I want him to talk about what he’s going to run on,” Mr. Wassel, 70, said.

Beyond Mr. Christie and Mr. Hutchinson, Republicans running for president were largely supportive of Mr. Trump, with some arguing that the prosecution amounted to an extraordinary and unfair political vendetta and one going so far as to bluntly promise to pardon him.

Vivek Ramaswamy, an entrepreneur who has positioned himself to secure the backing of Mr. Trump’s supporters if the former president’s legal problems derail his political comeback, said, “I commit to pardon Trump promptly on Jan. 20, 2025.”

In a radio interview on Friday before the indictment was unsealed, former Vice President Mike Pence seemed to contrast Mr. Trump’s conduct with his own diligent return of classified documents to the National Archives. But he added that he was “deeply troubled to see this indictment move forward” and took a swipe at what he called “years of politicization” of the Justice Department.

Meanwhile, Senator Mitt Romney of Utah, the Republican nominee for president in 2012 and a leading critic of Mr. Trump, was one of the few G.O.P. officeholders to condemn him, saying the former president had “brought these charges upon himself by not only taking classified documents, but by refusing to simply return them when given numerous opportunities to do so.”

Jonathan Weisman contributed reporting from Chicago, and Luke Broadwater from Washington.

Chris Christie, the former New Jersey governor now running for president, called the indictment against former President Donald Trump “devastating” on Friday evening.

“Is this the type of conduct that we want from someone who wants to be president of the United States?” he asked in an appearance Friday evening on CNN.

From Austin, Texas, to Jerusalem and Rome, their survival tactics have sometimes paralleled Mr. Trump’s playbook, aggressively working to delegitimize inquiries. Others have tried a different strategy, making efforts to appear sanguine as they denied wrongdoing.

In Israel, Prime Minister Benjamin Netanyahu won another term last fall despite a felony corruption case. Like Mr. Trump, Mr. Netanyahu has long cast cases against him as the equivalent of a “witch hunt” while seeking to dismiss members of law enforcement who threatened his standing as politically motivated.

In Italy, former Prime Minister Silvio Berlusconi, who became the country’s first sitting prime minister to testify as a criminal defendant, faced years of legal turmoil that he often rebuked by suggesting that proceedings against him amounted to efforts at a political coup.

Their messages are similar to Mr. Trump’s broadsides against America’s law enforcement system — and they are not the first politicians in legal trouble to attack that system.

Ahead of his federal corruption and bribery trial in 2002, then- Rep. James A. Traficant Jr., a Democrat from Ohio, declared: “I am not liked by the F.B.I. I am not liked by the Treasury. I am not liked by the courts. And you know what? Quite frankly, I don’t give a damn.”

Mr. Traficant became the fifth House member in history to be expelled from Congress.

There have been other candidates to run for office after being charged with or convicted of crimes, from Eugene V. Debs, the Socialist leader and anti-World War I activist who ran for president from prison in 1920, to Marion S. Barry Jr., who in 1994 won another mayor’s race in Washington, D.C., despite having been convicted on a cocaine charge.

In the last several years in Texas, a number of candidates have sought office under a cloud of legal questions.

Last year, the state’s attorney general, Ken Paxton, prevailed in both his primary contest and in the general election, even as a long record of legal troubles — including having been indicted and arrested on criminal securities-fraud charges — followed him through his campaigns. Throughout those races, he bear-hugged Mr. Trump, tried to dismiss the scrutiny as politically motivated and endeared himself to much of the Republican base by leaning into cultural battles.

His challenges, though, have caught up with him even within his own party: He was impeached by the Texas House last month, over charges that he had used his position to benefit himself and a campaign donor. On Thursday, that donor was arrested by the Travis County Sheriff’s Office on behalf of the F.B.I.

And in 2015, former Gov. Rick Perry of Texas announced a presidential bid despite having been indicted on two felony charges of abusing his official capacity and coercing a public servant.

Mr. Perry, denying wrongdoing, sought to project an air of confidence, smiling in a mugshot that went viral and going out for frozen custard with his legal team.

“The takeaway was that ‘this is a ridiculous indictment, a ridiculous process, and I’m going to approach it in an unflappable manner,’” said Ray Sullivan, who co-chaired a pro-Perry super PAC during that presidential election and had served as one of his top aides.

The case was later dismissed.

Katon Dawson, a former chairman of the South Carolina Republican Party, was a supporter of Mr. Perry’s during his relatively short-lived campaign.

“It hampered everything we did,” he said of the indictment against Mr. Perry. “It was something that took some of the steam out of our sails.”

But Mr. Dawson, who is supporting Nikki Haley — the former South Carolina governor who later served as United Nations ambassador — in the 2024 presidential race, was skeptical that Mr. Trump’s indictment would have a similar effect on him, at least for now, with Republican primary voters.

“He will get another bump in the polls,” Mr. Dawson predicted, saying that he expected many Republican voters to see the indictment as political. Still, he added, “That political capital runs out at some time. The question is, when does it run out and people say, ‘I’ve had enough.’”

Kitty Bennett contributed research.

But he emerged on Friday to make a concise case for his decision to charge Mr. Trump in connection with the former president’s retention of classified documents at his residence in Florida.

“Adherence to the rule of law is a bedrock principle of the Department of Justice,” he said. “And our nation’s commitment to the rule of law sets an example for the world. We have one set of laws in this country, and they apply to everyone. Applying those laws. Collecting facts. That’s what determines the outcome of an investigation. Nothing more. Nothing less.”

But visuals, as Mr. Trump has so often claimed, matter just as much as words — and Mr. Smith cut a striking figure.

He looked very much like a widely circulated photograph of him taken when he was a war crimes prosecutor in The Hague a couple of years ago, with the same graying beard, deeply lined face and solemnity — but without the black-and-purple judicial robe.

His team had considered waiting until Mr. Trump’s arraignment in Miami next week before issuing a public statement, according to several people close to the situation, but he seems to have decided that presenting a more complete rationale for his actions was needed to counter the narrative of political persecution put forth by Mr. Trump and his allies.

The decision to hold a news conference at Mr. Smith’s office, rather than at the department headquarters, was also tactical, intended to underscore Attorney General Merrick B. Garland’s distance from the decision-making process.

Mr. Smith spoke for just under three minutes, and took no questions, but in that time he delivered a defense of his team’s work, which Trump allies dismiss as a politically motivated witch hunt.

Still, Mr. Smith played down his own presence, casting the indictment as unavoidable, given what he described as “the gravity” of the crimes Mr. Trump, and his co-defendant, Walt Nauta, are accused of committing.

He ended by thanking his staff for “upholding the rule of law in our country,” then walked out of the room, ignoring questions and leaving news photographers staring at his image in their viewfinders.

Nevertheless, it would be extraordinary for a person who is under indictment, let alone convicted of a felony, to be a major party nominee.

There are only a few historical examples of somewhat serious candidates who even come close. They include the unsuccessful run in the 2016 Republican primary by Rick Perry, the former governor of Texas, after he was indicted on charges of abuse of power (the charges were dismissed months after he dropped out of the race), and the 1920 run by Eugene V. Debs as the Socialist Party nominee while he sat in prison for an Espionage Act conviction.

If Mr. Trump were to be elected president while a felony case against him was pending or after any conviction, many complications would ensue.

The Justice Department has in the past taken the position that even indicting a president while in office would be unconstitutional because it would interfere with the president’s ability to perform duties as head of the executive branch. Mr. Trump would surely try to get the case dismissed on that basis. There is no definitive Supreme Court ruling because the issue has never arisen before.

Notably, in 1997, the Supreme Court allowed a federal lawsuit against President Bill Clinton to proceed while he was in office. That was a civil case, however — not a criminal one. Mr. Trump also faces a state case, an indictment in Manhattan in April, where he is accused of falsifying business records related to a hush-money payment.

Even more extraordinary complications would arise were Mr. Trump to be convicted and incarcerated and yet elected anyway. One possibility is that he could win a federal court order requiring his release from prison as a result of a constitutional challenge. Another is that upon the commencement of his second term, he could be immediately removed from office under the 25th Amendment as “unable to discharge the powers and duties of his office.”

Mr. Jordan has for years vilified the F.B.I., and since taking the helm of the Judiciary panel he has been grasping for evidence that the bureau is corrupt and has unfairly targeted Mr. Trump and conservatives. The letter was Mr. Jordan’s latest effort to press those claims.

In it, he cited an interview his panel conducted this week with Steven D’Antuono, the former head of the F.B.I.’s Washington field office, whose concerns about the search warrant last year were detailed earlier by The Washington Post.

Mr. Jordan said that during his closed-door interview, Mr. D’Antuono had testified that he believed a search conducted with the consent of the former president — rather than a surprise search — would have been “the best thing for all parties involved,” including “the F.B.I., for former President Trump, and for the country.”

Mr. D’Antuono declined to comment about his interview.

Among the other concerns Mr. Jordan said Mr. D’Antuono had listed were that Washington officials, not the Miami field office, had conducted the search and that the F.B.I. did not wait until one of Mr. Trump’s lawyers was present to begin the search.

But Mr. Jordan omitted several facts from his letter in an apparent effort to place Mr. D’Antuono’s account in the worst possible light.

Mr. D’Antuono has told associates that he was not opposed to executing the search warrant, but wanted to give Mr. Trump’s legal team one last chance to hand over the documents before sending agents into his club — a position that his superiors overruled.

Prosecutors believed that Mr. Trump’s lawyers had already misled them once, falsely certifying to the F.B.I. and the Justice Department that they had searched for documents at the club and turned over everything they could find. The 37-count indictment against Mr. Trump and one of his aides released on Friday laid out in detail the actions the former president took to deceive prosecutors and cause the lawyers to make the false certification.

Mr. D’Antuono has also told associates that he was worried about the optics of F.B.I. agents entering Mr. Trump’s property in raid jackets, given the continued vilification of the bureau by the former president and his supporters.

Mr. D’Antuono also believed that the Miami field office should have been more involved in the investigation because of its proximity to Mr. Trump’s resort and the substantial Jan. 6 investigation that had consumed the Washington field office’s resources, according to the account he gave associates. But he told Mr. Jordan during the interview that he understood that his counterintelligence agents were involved because they were experts on the matter, according to a portion of the interview transcript released by Democrats on the panel.

And Mr. D’Antuono told him that the prosecutors handling the Trump case had not done anything wrong, another assertion that Mr. Jordan did not mention in his letter.

Democrats on the panel said Mr. D’Antuono provided information that did not portray Mr. Trump favorably.

Mr. D’Antuono told the panel how the classified documents hidden at Mar-a-Lago included documents so highly sensitive that not even he, as the head of the office, could read them, according to excerpts from his transcript released by the committee’s Democrats. Mr. D’Antuono testified he had to call in outside help to prevent further “spillage” of those classified materials.

And Mr. D’Antuono testified that Mr. Trump was physically present for a key act of potential obstruction, according to excerpts. Mr. Trump was standing with one of his lawyers at the steps of Mar-a-Lago when the lawyer handed investigators the letter falsely certifying that all classified documents had been returned, Mr. D’Antuono testified.

During that meeting, Mr. Trump told the F.B.I. and Justice Department officials that he was “open book.”

From January through March 15, 2021, some of TRUMP’s boxes were stored in The Mar-a-Lago Club’s White and Gold Ballroom, in which events and gatherings took place. TRUMP’s boxes were for a time stacked on the ballroom’s stage, as depicted in the photograph below (redacted to obscure an individual’s identity). Page 10.

In April 2021, some of TRUMP’s boxes were moved from the business center to a bathroom and shower in The Mar-a-Lago Club’s Lake Room, as depicted in the photograph below. Page 12.

On June 24, 2021, TRUMP's boxes that were in the Lake Room were moved to the Storage Room. After the move, there were more than 80 boxes in the Storage Room, as depicted in the photographs below. Page 13.

On December 7, 2021, NAUTA found several of TRUMP’s boxes fallen and their contents spilled onto the floor of the Storage Room, including a document marked “SECRET//REL TO USA, FVEY,” which denoted that the information in the document was releasable only to the Five Eyes intelligence alliance consisting of Australia, Canada, New Zealand, the United Kingdom, and the United States.

NAUTA texted Trump Employee 2, “I opened the door and found this…” NAUTA also attached two photographs he took of the spill. Trump Employee 2 replied, “Oh no oh no,” and “I’m sorry potus had my phone.” One of the photographs NAUTA texted to Trump Employee 2 is depicted below with the visible classified information redacted. TRUMP’s unlawful retention of this document is charged in Count 8 of this Indictment. Page 14.

On November 12, 2021, Trump Employee 2 provided TRUMP a photograph of his boxes in the Storage Room by taping it to one of the boxes that Trump Employee 2 had placed in TRUMP’s residence. Page 18.

“I’m more concerned about all the political leaders who have quickly lined up behind Donald Trump,” Mr. Hutchinson said in an interview Friday afternoon after reading the indictment. “I don’t think that’s wise for the rule of law.”

Mr. Hutchinson said he was taken aback by the sensitivity of many of the documents in question, and especially by the details that buttress the charge of obstruction of justice, which he said “seemed premeditated” on the part of Mr. Trump.

“It’s going to be very difficult to respond to” the obstruction charge, he said of Mr. Trump and his legal team.

But his strongest criticism was for the Republicans, including several of his rivals running against Mr. Trump for the party’s presidential nomination, who quickly condemned the Justice Department’s case as a political prosecution devised only to deny Mr. Trump another term.

“It would be doing a disservice to the country if we did not treat this case seriously,” said Mr. Hutchinson, whose bid is considered a long shot. It would also be an affront to anyone “who believes our secrets ought to be protected” and to those who “have a high regard for our intelligence community,” he added.

“This country didn’t vote for an altar boy. Everybody has skeletons in the closet,” said Peter Demopoulos, 68, who operates a cattle farm in Fredonia, Wis., a rural village about 30 miles north of Milwaukee.

Mr. Demopolous, who moved to the United States from his native Greece in 1971, said he had voted for Mr. Trump in the two previous elections and would vote for him again in the coming Republican primary, whether or not he’s found guilty in the documents case or in other investigations.

“Everybody comes here for a reason, to be successful,” he said. “And I think having Trump or somebody like Trump, I think it’s a beautiful thing — to create jobs, to do the right thing, to motivate people.”

It is far too early to measure the political impact of the latest indictment. A Yahoo-YouGov poll conducted last month found that while majorities of Democrats and independents considered removing “highly classified documents from the White House and obstructing efforts to retrieve them” a serious crime, Republicans were more divided. The poll found 42 percent of Republicans called it a serious crime, while 35 percent said it was not serious, and 22 percent said they were not sure.

As Mr. Trump continues to portray the investigations against him as a vast conspiracy, some Republican voters repeated those claims and echoed what they see as Mr. Trump’s achievements in office. Others were more unsure about how much weight to give the federal indictment and how to factor it into a voting decision in 2024.

In Pennsylvania, Don Fretz, 76, a registered Republican, said he had voted “grudgingly” for Mr. Trump in 2016 and 2020 but after the new indictment, was unwilling to do so again. He hoped to vote for another Republican nominee in 2024, he said.

“I think the man should step down,” from the race, Mr. Fretz, a retiree, said outside a convenience store in Souderton, Pa. “He has too much baggage. He has great policies, but he doesn’t know when to be quiet.”

John Lanser, 60, who does masonry work among other construction-related tasks, stopped at a bakery in the Fredonia area in Wisconsin on Friday morning to get doughnuts while on his way to pick up a load of cement. He voted for Trump in both 2016 and 2020 and plans to support him again, regardless of his legal situation.

“People didn’t like Trump or who he was,” Mr. Lanser said. “But what he did for the country was great.”

Mr. Lanser said that the former president’s leadership yielded results.

“Gas prices were lower,” he said. “The economy was good. Everything was better in terms of cost of living than what it is now.”

Heather Stein, a businesswoman in Pennsylvania, said she had not voted for Mr. Trump in past elections and didn’t plan to vote for him or President Biden if they are the nominees in 2024. Still, she said she didn’t understand why Mr. Trump was being charged in connection with taking classified documents after his term ended.

“Every president leaves the White House with boxes of stuff,” she said outside a supermarket in Blue Bell, Pa., hours before the indictment was unsealed. “It could be that there was something egregious in the documents, I don’t know. But I don’t have a lot of faith in that process at the moment.”

Ms. Stein, 47, who did not specify a political affiliation, said she might be tempted to vote for a third-party candidate in 2024.

“I wish they would both just go away,” she said of Mr. Trump and Mr. Biden. “I’m not more or less likely now to vote for either of them. I want one of those T-shirts that says, ‘Any functioning adult 2024.’”

Mr. Trump, according to the indictment, states he has found a document that was a plan of attack against an unnamed country. One quotation in the indictment suggests Mr. Trump showed the document to the writer and possibly even provided the document to read.

“See, as president I could have declassified it,” Mr. Trump said, according to the indictment.

“Now I can’t, you know, but this is still a secret,” Mr. Trump goes on to say.

A staffer responds, laughing: “Yeah. Now we have a problem.”

The recording could present a problem for Mr. Trump’s defense, showing he knew some of the documents he kept remained classified, and that he should not be showing them to people without security clearances, like the writer.

The conversation that was recorded by the writer — who was assisting Mark Meadows, one of Mr. Trump’s former chiefs of staff, with a book — and took place on July 21, 2021. Around that time, media reports were discussing the concerns of Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, who, according to the reports, said that Mr. Trump had considered attacking Iran.

The indictment neither identifies General Milley nor Iran.

Current officials declined to comment, but some former officials said they believed the country in question was Iran, given that in Mr. Trump’s final year in office he discussed potential attacks on Iran with defense and military officials multiple times.

The Pentagon’s operational plans for attacks on adversary countries are among the most closely guarded secrets. But such plans are technical in nature, and not usually shared with presidents, particularly one who was not interested in details, like Mr. Trump. However, the military did create summary documents to show Mr. Trump about contingency plans, former officials said.

While any document outlining a potential plan of attack would constitute secret defense information protected by the Espionage Act, it is possible the document Mr. Trump said was secret was not marked as such.

The indictment lists 31 specific documents the government accuses Mr. Trump of keeping, almost all marked secret or top secret. Some have an additional marking of “special handling.” It suggests the material inside was especially sensitive, potentially including information about the method of collection, and that specific procedures were in place for its storage, handling and who could see it.

It is not precisely clear which of the documents listed by the special counsel was the one Mr. Trump showed off in July at Bedminster. While the descriptions of the classified documents are vague, a number are described as containing information about the military capabilities of a foreign country.

But one document, listed in the indictment as undated and without markings about its classification level, is described as “concerning military contingency planning,” a description that could mean it described a war plan, like the one Mr. Trump showed off at the golf club.

If that is the case, potential jurors would be pulled from the voter registration rolls of Palm Beach County, according to the federal court’s policy. Voters in the county have consistently voted for Democratic presidents by a substantial margin, even as the county and some neighboring areas, such as Miami-Dade County to the south, have grown more Republican in recent years.

In 2020, President Biden won 56.1 percent of the votes in Palm Beach County to Mr. Trump’s 43.3 percent. However, Gov. Ron DeSantis, a Republican, won 51 percent of the county vote in the governor’s race last fall, edging out a less popular Democratic challenger.

Mr. Trump is scheduled to make his first appearance in the case at the federal courthouse in Miami on Tuesday, suggesting that any potential trial may take place there. That brings with it a possibility that lawyers could argue — for a variety of reasons, including the logistical burden on the jurors themselves — that jurors should be selected from Miami-Dade County. Mr. Biden won that county in 2020, but by only seven points after many Hispanics swung to Mr. Trump. Mr. DeSantis won 55 percent of the county’s vote last fall.

Scott E. Sundby, a criminal law professor at the University of Miami who studies juries, said that no matter where jurors are chosen from, the publicity surrounding the case — and the fact that Mr. Trump is a high-profile politician — would make it much more difficult for the court to find jurors able to decide the case solely on the facts presented at trial. Many prospective jurors — and even those who make their way onto the jury — would likely have heard of the case, he added.

“You can’t strike people just because they’ve heard about the case unless you’re going to find a hermit in the middle of the Everglades,” Mr. Sundby said. “It’s going to be a real challenge for the judge. It’s going to take a real skillful judge to navigate this.”

The case was assigned to Aileen M. Cannon, whom Mr. Trump appointed to the bench in 2020.

In the jury selection process, lawyers can strike a limited number of potential jurors for any reason except for race and gender. Mr. Sundby said that lawyers from both sides will want to know as much about the potential jurors as possible, including their political views. But the judge handling the case will ultimately decide what questions to allow, he said, and whether lawyers will be able to interview jurors directly or submit questions to be asked by the judge.

Mr. Sundby said it is possible, for example, that a judge could keep lawyers from expressly asking jurors who they voted for but may allow questions that could reveal their political and moral views.

“If the criminal justice system is going to come out of this, hopefully still standing, it’s really important that the process be made as apolitical as possible,” he said.

The valets in the White House have unusual proximity to the commander in chief, encountering them at moments of vulnerability, including at meals and on foreign trips.

Mr. Trump and Mr. Nauta forged a bond during the Trump administration, and when the term ended, Mr. Nauta retired and went to go work for Mr. Trump personally.

He was one of the very few members of Mr. Trump’s post-presidential office when Mr. Trump first returned to private life at his club, Mar-a-Lago, in Palm Beach, Fla. There, Mr. Nauta resumed the kind of personal chores that he had helped Mr. Trump with while he was president.

Mr. Nauta has been seen as deeply loyal to Mr. Trump by other aides.

But he attracted the attention of the government for his appearance on security camera footage from the club, which was subpoenaed by prosecutors, moving boxes in and out of a basement storage room after a grand jury subpoena.

In interviews with government officials, according to the indictment, he gave false testimony about whether he had moved boxes to Mr. Trump’s residence earlier in the year. In reality, according to the indictment, Mr. Nauta brought several boxes to Mr. Trump’s residence from the storage room at a time when National Archives officials were seeking the return of presidential material, but he told investigators he didn’t.

In another memorable moment noted in the indictment, on Dec. 7, 2021, Mr. Nauta discovered that some of the boxes in the storage room had fallen and their contents were all over the floor, “including a document marked ‘SECRET//REL TO USA, FVEY,’ which denoted that the information in the document was releasable only to the Five Eyes intelligence alliance consisting of Australia, Canada, New Zealand, Britain and the United States.”

Mr. Nauta texted a colleague and wrote, “I opened the door and found this…”

Prosecutors have been weighing charging Mr. Nauta since the fall, but had been pressuring him to cooperate with their investigation. He declined.

His indictment on Thursday is certain to bring a glaring spotlight to the state conventions in Georgia and North Carolina on Saturday, as it will be the first time he plans to appear publicly since he became the first former president in American history to face federal charges.

Two speeches by Mr. Trump on the same day in two states are likely to eclipse the appearances of his Republican rivals, consuming the attention of state G.O.P. activists and elected officials as well as the media.

Many in the Republican field have been fanning out across the South and Southwest, raising campaign cash and cementing relationships with party leaders in a number of traditionally delegate-rich and donor-heavy states. Those states — including Texas and Georgia — may be critical in shaping the course of the primary race, after the early-voting states of Iowa, New Hampshire, South Carolina and Nevada have their say next year.

The first states to vote play an outsize role in defining the race, and those who fail to gain traction in at least some of those contests generally collapse. (President Biden was something of an anomaly; he lost the first three Democratic contests before South Carolina revived his candidacy and later-voting states cemented his victory.)

But pitched presidential primary battles often stretch well past the initial early window as candidates compete to clinch the nomination, with a tranche of delegates typically up for grabs on Super Tuesday, when many states hold primaries at once. With their latest forays, some of the 2024 G.O.P. candidates are signaling an early interest in building their profiles in those later-voting states, even as others have focused on those states primarily for fund-raising purposes.

In addition to Mr. Trump, two long-shot candidates were also scheduled to appear in Georgia: former Gov. Asa Hutchinson of Arkansas and Vivek Ramaswamy, the entrepreneur and “anti-woke” activist.

“We’re planting the seeds,” Mr. Ramaswamy said of his trip to Georgia.

Mr. Trump, Mr. DeSantis and former Vice President Mike Pence were slated to speak to the North Carolina Republican Party’s state convention, with Mr. DeSantis listed as a keynote speaker at a Friday night dinner, and Mr. Pence and Mr. Trump lined up for Saturday, according to the latest schedule.

“I would think everybody should be and would be focused on a delegate strategy, because that really is going to determine what happens in Milwaukee next year,” said Michael Whatley, the chairman of the North Carolina Republican Party, referring to next year’s Republican National Convention in Wisconsin. Mr. Whatley said he expected that “every activist, county party leader, district party leader and donor in the entire state is going to be descending on Greensboro” for the state convention.

It may be a different scene in Georgia, where the state G.O.P. has veered hard to the right — even as Mr. Trump lost Georgia to Mr. Biden, and Democrats hold both Senate seats there, their victories driven in part by backlash to Mr. Trump’s brand of grievance-laced politics.

Brian Kemp, Georgia’s Republican governor, and other Republican officeholders in the state — who prevailed in primaries last year even as Mr. Trump endorsed their opponents — are expected to stay away.

“The group that goes to Republican conventions is one group of Republicans, but not the Republicans,” said former Representative Jack Kingston, a Georgia Republican, nodding to the split in the party.

Prosecutors revealed that Trump had caused his lawyers to falsely certify a statement for the Justice Department last June that his legal team had conducted a “diligent search” of Mar-a-Lago and found only a few files that had not been returned to the government.

Prosecutors said that Christina Bobb, his lawyer, signed the statement even though she had no role in the review of the boxes. Shortly after Bobb did the false certification, officials from the F.B.I. and Justice Department met at Mar-a-Lago with Trump and Bobb along with another lawyer. Trump declared to investigators that he was an “open book.”

The indictment charged that after the grand jury issued a subpoena requiring the former president to turn over “all documents with classification markings,” he tried to block the F.B.I. and grand jury investigations and “conceal his continued retention of classified documents.”

The indictment says he did so by suggesting that his attorney falsely tell the F.B.I. and grand jury that he did not have the documents the grand jury was seeking. The indictment also accuses Trump of directing his valet to move boxes of documents to hide them from the former president’s lawyer, the F.B.I., and the grand jury.

Here are some of the most significant, and startling, allegations:

Mr. Trump and Mr. Nauta are accused of conspiring to obstruct justice.

Prosecutors say they have assembled evidence showing that Mr. Trump willfully ignored a May 2022 subpoena requiring him to return everything belonging to the National Archives — and took extraordinary steps to obstruct the F.B.I. and grand jury.

In the hours before Mr. Trump’s lawyer visited his Mar-a-Lago estate to search for documents in a storage room — an attempt to comply with the subpoena — Mr. Trump directed Mr. Nauta, his co-defendant, to move 64 of the boxes out of the storage room because he maintained they were his property.

“I don’t want anybody looking through my boxes, I really don’t,” Mr. Trump told one of his lawyers, according to the indictment.

He stored boxes of important documents in the shower.

The indictment says that in April 2021, Mr. Trump’s employees needed to move dozens of boxes from a ballroom space they were converting to office space. “There is still a little room in the shower where his other stuff is,” one aide texted another. Soon after, the boxes were hauled to a small bathroom adjacent to a Mar-a-Lago banquet room and piled up nearly to the tiny chandelier next to the toilet.

Top secret documents were stored so sloppily they spilled onto the floor.

One of the most striking images in the document is a picture of a box of top secret national security documents that in 2021 had spilled on the floor of a Mar-a-Lago storage room accessible to many of the resort’s employees. The files were marked with restrictive “five eyes” classification markings, indicating they could only be viewed by officials with top security clearances issued by the United States and its closest allies.

Mr. Trump suggested his lawyer take a folder of documents and ‘if there’s anything really bad in there, like, you know, pluck it out.’

In one of the most problematic pieces of evidence for Mr. Trump, the indictment recounts how, according to his lawyer’s words, Mr. Trump and the lawyer discussed what to do with a folder of 38 documents with classification markings. The lawyer said Mr. Trump made a “plucking motion” that implied, “why don’t you take them with you to your hotel room and if there’s anything really bad in there, like, you know, pluck it out.”

That could indicate that he knew he was holding onto sensitive documents, the “bad” ones, authorized people without appropriate security clearances to vet them — rather than simply returning everything to the archives, as the government demanded.

Mr. Trump shared secrets with visitors to Bedminster. There’s audio.

Many of the episodes recounted in the filing have been reported in the news media — including a potentially damaging revelation that he was recorded showing off secret U.S. battle plans — describing the material as “highly confidential” and “secret,” while admitting it had not been declassified.

“See, as president I could have declassified it,” Mr. Trump said. He added, “Now I can’t, you know, but this is still a secret.”

A secret map was said to be shared with a political action committee staff member.

In another incident in August or September 2021, he shared a top secret military map with a staff member at his political action committee who did not have a security clearance.

According to the indictment, the former president suggested that a military operation in an unnamed country was not going well. He showed the map to the staff member but, according to the indictment, warned the person “not to get too close.”

In these interactions, he seemed to be less interested in the content of the material, than the fact that they had been “presented to me,” like a gift or a keepsake.

“Isn’t it amazing?“ he asked one visitor after showing off a document, adding that he had randomly plucked the papers off “a big pile,” suggesting he had many more.

M. Evan Corcoran, one of Trump’s lawyers, is a key witness.

Mr. Corcoran, who kept meticulous notes (some of them transcribed from iPhone voice memos he made for himself), found himself in the position of pressuring his evasive client into doing both the lawful and self-protective thing by returning the documents to the government.

In one of the more stunning revelations, prosecutors said that Mr. Trump and Mr. Nauta moved around boxes so that Mr. Corcoran, who requested a full accounting of the material to provide to investigators, could not find them.