Over the past month, the United States has faced simultaneous crises thousands of miles apart. In the skies over Taiwan and along the border with Ukraine, China and Russia have tested the new U.S. president and the U.S.-led international order. In the unipolar era of decades past, even the prospect of such geopolitical tension would have seemed fanciful. So preeminent was the United States that it enshrined the ability to deter—and, if necessary, win—two regional wars at the same time in its defense planning, describing such a capacity as the essential condition of a superpower.
