Every presidency is an evolution because every presidency subjects the ideas that a leader brings into office to the test of global affairs. Nearly three years into Joe Biden’s tenure, the world keeps breaking his bedrock assumptions. After Hamas’ attack on Israel, Biden’s foreign policy is entering its third phase — one that features crises nearly everywhere and one for which his administration is, intellectually and materially, ill-prepared.

It’s hard to remember now, but Phase One of Biden’s strategy aimed to defuse tensions in two of Eurasia’s three key theaters. The US, Biden believed, must pour its energy into countering the threat from China, the one actor that could challenge America around the globe. This required pursuing mini-detentes with other, presumably less threatening adversaries: a “longer and stronger” nuclear deal with Iran and a “stable and predictable” relationship with Russia. Ruthless prioritization, it seemed, was essential to meeting the challenge that mattered most.