The United States can still fight and win two major wars at the same time, or at least come near enough to winning that neither Russia nor China would see much hope in the gamble. The United States can do this because it continues to maintain the world’s most formidable military, and because it stands at the head of an extremely powerful military alliance.
The United States discarded its oft-misunderstood “two war” doctrine, intended as a template for providing the means to fight two regional wars simultaneously, late last decade. Designed to deter North Korea from launching a war while the United States was involved in fighting against Iran or Iraq (or vice versa,) the idea helped give form to the Department of Defense’s procurement, logistical and basing strategies in the post–Cold War, when the United States no longer needed to face down the Soviet threat. The United States backed away from the doctrine because of changes in the international system, including the rising power of China and the proliferation of highly effective terrorist networks.
But what if the United States had to fight two wars today, and not against states like North Korea and Iran? What if China and Russia sufficiently coordinated with one another to engage in simultaneous hostilities in the Pacific and in Europe?
Could Beijing and Moscow coordinate a pair of crises that would drive two separate U.S. military responses? Maybe, but probably not. Each country has its own goals, and works on its own timeline. More likely, one of the two would opportunistically take advantage of an existing crisis to further its regional claims. For example, Moscow might well decide to push the Baltic States if the United States became involved in a major skirmish in the South China Sea .