After almost eighty years of constancy in global strategic approach underwriting a worldwide Pax Americana, the United States in 2025 found itself at a grand strategy crossroads. The second Trump administration began moving away from support for Pax Americana and toward an America First 2.0 grand strategy. The latter is far less committed to the American post-World War II multilateral international order project aimed to assure relative peace and stability through global norms and institutions dedicated to capitalism, free trade, liberal democracy, national self-determination, and respect for individual human rights. A review of American relative strengths vis-à-vis its global great power strategic rivals, China and Russia, indicates that Washington today possesses sufficient relative military, politico-diplomatic, and ideological power to achieve the main strategic aims of either America First 2.0 or Pax Americana over the coming five years. However, America First 2.0’s devaluation of multilateral security commitments and reluctance to underwrite liberal political and free trade norms are likely to accelerate future American relative economic decline and leave the USA increasingly vulnerable to assertive Chinese military moves, especially in the Western Indo-Pacific region.