Today, war in Ukraine, conflict in the Middle East, and brewing tensions in the Indo-Pacific—stemming from both China and North Korea—present challenges for the United States military’s ability to effectively meet the demands placed on it. In the coming years and decades, the United States’ enduring military advantage will only be tested further, when facing the challenge of technologically, economically, and militarily prevailing against two great-power rivals, China and Russia, and simultaneously dealing with other conflicts in an increasingly unstable geopolitical environment.