Today, the U.S. House Foreign Affairs Committee will hold an important hearing focusing on a perennially difficult topic: how to reform and update the 2001 Authorization for Use of Military Force (AUMF), which was enacted in response to the 9/11 attacks and continues to provide the main legal basis for global U.S. counterterrorism operations more than two decades later.

But as legislators prepare for what is certain to be a contentious debate, they are leaving a lower-hanging fruit to wither on the vine: specifically, a long-standing bipartisan proposal to repeal the separate 2002 AUMF that authorized the U.S. invasion of Iraq. While the Senate overwhelmingly passed a repeal measure in March, the House has spent the past several months dawdling on its own proposal, despite substantial bipartisan support.

At first glance, a repeal of the invasion authorization may seem like a symbolic gesture. After all, the main body of U.S. troops in Iraq withdrew more than a decade ago, and the small force that remains ceased combat operations in 2021. And the Biden administration, which supports the repeal, has made clear that it would have no impact on ongoing U.S. military operations.

But focusing on current operations misses what repeal would accomplish. More than 20 years of practice has substantially expanded the effective scope of the 2002 Iraq AUMF, making it susceptible to unexpected uses beyond its original motivation of removing Iraqi dictator Saddam Hussein from power—including in ways that could allow a future president to bypass Congress while pursuing another major war in the Middle East. Repeal is the only way to ensure this doesn’t happen, and a prudent step that the House should take regardless of where the broader debate over AUMF reform might lead.

When Congress first enacted the 2002 Iraq AUMF, there was little ambiguity about how it would be used. The George W. Bush administration had been building the case for toppling Hussein, and the AUMF was a response to Bush’s request for congressional support. But the text that Congress enacted was notably less specific, as it authorized the use of force both to enforce relevant U.N. Security Council resolutions and “as [the president] determines to be necessary and appropriate in order to defend the national security of the United States against the continuing threat posed by Iraq.”

As we all know, the U.S. and coalition forces that entered Iraq in March 2003 quickly found that regime change was not as straightforward as it seemed. Resistance came not just from regular Iraqi military forces but from irregular forces and foreign fighters actively supporting the regime across Iraq. Other armed groups were working to advance their own agendas amid the post-invasion chaos, ranging from Iran-backed resistance movements to Iranian dissident group Mujahedeen-e-Khalq.

As the U.S. role in Iraq transitioned from invader to occupying authority, the military mission changed as well. Suddenly, U.S. and allied soldiers were responsible not just for deposing the Hussein regime but for defending Iraq against external threats and preserving its internal security against a rising tide of sectarian violence. This brought U.S. forces into conflict with different factions within Iraq, including remnants of regime sympathizers, Shiite militias, and the violent extremist movement that would come to be called al Qaeda in Iraq (AQI). On a handful of occasions, it even led the U.S. military to mount operations aimed at capturing Iranian agents who the United States believed were fomenting violence through their support of Shiite militias around the country.

The 2002 AUMF was the main statutory authorization under which U.S. troops engaged in these activities. While Bush’s attorneys advanced a broad view of his ability to direct such action on his own constitutional authority, his administration was careful to point to the 2002 AUMF as the legal basis for most of its actions, including by complying with certification and reporting requirements that kept Congress abreast of how the law was being used.

By 2008, the Bush administration maintained that, while “the Saddam Hussein regime was the primary threat posed by Iraq” at the time the 2002 AUMF was enacted, “Congress recognized it was not the only threat.” In the administration’s view, Congress had intended to authorize the use of force more broadly, including against al Qaeda and other terrorist groups in Iraq. Moreover, as the authorization to address the “continuing threat posed by Iraq” was distinct from the authorization to enforce U.N. Security Council resolutions, it was not contingent on the U.N. mandate for the multinational force that ended later that year.

The Obama administration largely continued these activities until the U.S.-Iraqi security agreement that replaced the U.N. mandate expired at the end of 2011. At that point, following a failed effort to negotiate a new agreement with Baghdad, Washington withdrew U.S. troops and ceased relying on the 2002 AUMF for the first time since 2003. Senior administration officials even expressed support for its repeal on the logic that the 2002 AUMF was no longer needed.

But in June 2014, the extremist group that would soon be known as the Islamic State surged through northern Iraq. At the Iraqi government’s urgent request, the Obama administration intervened once again, targeting the Islamic State with airstrikes in Iraq and nearby Syria as the opening of what would become a larger multilateral military campaign. The main legal justification for these actions was not the 2002 Iraq AUMF, but the separate 2001 9/11 AUMF. Specifically, the administration argued that the Islamic State was a successor to AQI, which in turn had splintered off from al Qaeda, a main target of the 2001 AUMF. But the Obama administration also cited the 2002 Iraq AUMF as alternative legal grounds for operations in Iraq and nearby parts of Syria.

In explaining this position, the Obama administration argued that the 2002 AUMF had “always been understood to authorize the use of force for the related purposes of helping to establish a stable, democratic Iraq and addressing terrorist threats emanating from Iraq.” “After Saddam Hussein’s regime fell in 2003,” it elaborated in a later report, “the United States continued to take military action in Iraq under the 2002 AUMF to further these purposes”—including by combating al Qaeda in Iraq. In the Obama administration’s view, “Congress ratified this understanding of the 2002 AUMF by appropriating billions of dollars to support continued military operations in Iraq between 2003 and 2011,” confirming the understanding that the 2002 Iraq AUMF authorizes the use of force against AQI and related terrorist threats.

Yet this interpretation did not stop with the Islamic State. In 2020, the Trump administration cited the 2002 Iraq AUMF—alongside the president’s authority under Article II of the U.S. Constitution—as the legal justification for the airstrike that killed Qassem Suleimani, the commander of the paramilitary Quds Force within Iran’s Islamic Revolutionary Guard Corps. In justifying this move, the U.S. Justice Department argued that “the Qods Force would continue to undermine stability in Iraq and … threaten U.S. personnel” if left unaddressed, placing the Suleimani strike in line with the 2002 Iraq AUMF’s dual purposes. The question remains, however, what other entities might find themselves in a similar position.

There is much to criticize about how the executive branch arrived at this understanding of the 2002 Iraq AUMF. But at this point, there is little to be done about it. Even if U.S. President Joe Biden were to repudiate this view, a future president could return to it. And while the federal courts could step in, they have thus far declined to do so on the grounds that there is, in the words of one district court judge, “no impasse or conflict between the political branches”—in other words, because Congress has taken no concrete steps to oppose it. Clear legislative action is the only way to roll it back.

What would repeal mean in practice then? The Biden administration is no doubt correct that it would not affect any ongoing military operations. Counterterrorism operations in Iraq and Syria are primarily authorized by the separate 2001 AUMF, which will remain in place even if the 2002 Iraq AUMF is repealed. And the executive branch maintains that the U.S. Constitution gives the president broad authority to use military force in pursuit of U.S. interests, including in defense of U.S. diplomatic and military personnel—authority that Biden has used against Iran-backed Shiite militias multiple times since entering office.

But this doesn’t make repeal meaningless. Recent presidents have acknowledged that there may be constitutional limits on their ability to engage in hostilities that are expected to lead to an armed conflict of substantial “nature, scope, and duration.” Similarly, while the 1973 War Powers Resolution allows the president to use military force on his own authority, it also demands that he stop within 60 to 90 days unless Congress gives its approval (or cannot convene). These restrictions—with which the executive branch generally complies, even though it sometimes pushes their boundaries or questions their constitutionality—are supposed to lock away the president’s ability to start a major, extended war without Congress. Statutes like the 2002 Iraq AUMF, however, provide the key to open that lock.

Leaving open the door to a major armed conflict could lead to bad outcomes in many corners of the world. But in the context of Iraq, one factor makes it particularly concerning: the regime in Iran, which has spent years trying to maximize its influence in Iraq while weakening Iraqi political institutions. In particular, it has supported an array of Shiite militias that act with impunity across Iraq, including by targeting both the government and U.S. diplomatic and military facilities with rocket attacks. It is not hard to imagine some future president following the Trump administration’s lead and framing these actions as threats to “a stable, democratic Iraq” or as “terrorist threats emanating from Iraq,” putting Iran itself squarely within the 2002 Iraq AUMF’s crosshairs.

Perhaps there will be a legitimate case for such military action one day. But if there is, then the president should make his or her case to Congress and the American people, not rely on a decades-old statute designed for a very different purpose. And if Congress still wants to have a role in such debates, then it needs to cut off the routes around congressional authorization that the executive branch has made clear it believes are open. Repealing the 2002 Iraq AUMF would be one important step in this direction.