**US military operations against Iran began in late February 2026 without a congressional declaration of war, relying instead on presidential authority as commander in chief amid disputes over the War Powers Resolution.** Ongoing naval blockade of Iranian ports, indirect diplomacy through Qatari mediators, and rejected Iranian proposals to reopen the Strait of Hormuz have kept tensions elevated into October, with both sides preparing for possible post-election escalation after the November 3 midterms. President Trump has signaled openness to renewed strikes while pursuing a deal on nuclear issues and sanctions relief, and Iran has faced severe economic strain without softening core positions. Formal congressional action to declare war remains rare in modern U.S. practice and would require specific legislative steps distinct from authorizations for use of military force or targeted operations. Upcoming force posture changes and any post-midterm diplomatic or military developments could influence market assessments of the likelihood of an official declaration.