John Ratcliffe's secret trip to Moscow to warn Russia against striking NATO members marks a return to credible deterrence after years of weakness that invited aggression from Moscow and Beijing alike. This matters because it signals to adversaries that American red lines are real again, shielding the alliance without dragging the United States into new wars or endless aid sprees. The Constitution places foreign affairs and national defense squarely with the executive to act decisively for the common defense, not to outsource security to international bodies or pretend every conflict demands congressional micromanagement. Federalism and limited government thrive only when the central authority fulfills its core duty to deter threats that could engulf the republic, leaving states and citizens free from foreign entanglements. Strength projected early prevents the larger calamities that weaken the nation at home.