That makes the Ukraine crisis a crucial test of American global power. Four years of Donald Trump’s “America First” chaos abroad, combined with political and social polarization and a failed response to the coronavirus pandemic at home, have fueled the perception around the world that America is a superpower on its last legs—one too divided, overstretched, and just plain weary to sustain its far-flung commitments. This narrative, which Biden’s botched withdrawal from Afghanistan only reinforced, seems to have taken hold within the Chinese leadership and has become a regular theme of official propaganda. As Xi, Putin, and other autocrats intensify their efforts to roll back American power, the U.S. is facing the stiffest challenge to its global primacy since the fall of the Soviet Union.

The fate of Ukraine has become intimately entangled in this renewed big-power competition. If Biden is firm, deft, and a little lucky, a series of talks this week among Russia, the U.S., and its allies in the North Atlantic Treaty Organization will lead to a compromise and avoid a Russian invasion of Ukraine. Yet a stalemate persists over Ukraine’s potential membership in NATO—which Putin desperately wishes to prevent. At stake is the balance of power between the U.S. and Russia in Eastern Europe. The outcome, though, could reverberate well beyond the region, and well into the future, affecting whether American power will remain strong enough to maintain peace and advance democracy—or whether the world’s autocracies will claw back clout that they lost decades ago.