Today, Putin seeks at the very least a two-tier NATO, in which no allied forces are deployed on former Warsaw Pact territory. The inevitable negotiations over this and other elements of a new European security “architecture” would be conducted with Russian forces poised all along NATO’s eastern borders and therefore amid real uncertainty about NATO’s ability to resist Putin’s demands

This takes place, moreover, as China threatens to upend the strategic balance in East Asia, perhaps with an attack of some kind against Taiwan. From a strategic point of view, Taiwan can either be a major obstacle to Chinese regional hegemony, as it is now; or it can be the first big step toward Chinese military dominance in East Asia and the Western Pacific, as it would be after a takeover, peaceful or otherwise. Were Beijing somehow able to force the Taiwanese to accept Chinese sovereignty, the rest of Asia would panic and look to the United States for help.

These simultaneous strategic challenges in two distant theaters are reminiscent of the 1930s, when Germany and Japan sought to overturn the existing order in their respective regions. They were never true allies, did not trust each other and did not directly coordinate their strategies. Nevertheless, each benefited from the other’s actions. Germany’s advances in Europe emboldened the Japanese to take greater risks in East Asia; Japan’s advances gave Adolf Hitler confidence that a distracted United States would not risk a two-front conflict.