Congress blocks measure to limit Trump’s military action against Iran

A party-line vote in Congress blocked a measure that would restrict President Trump’s authority to escalate military actions against Iran. The Polymarket contract on a U.S. declaration of war on Iran by December 31 sits at 7.5% YES.

The resolution’s defeat means Congress won’t constrain further military action. The December 31, 2026 market holds at 7.5%, unchanged from a week ago. The April 30 market is at 0.7% YES. Traders see almost no chance of a declaration in the near term but assign some probability to longer-term escalation.

Combined 24-hour volume was $38,191 in face value but only $329 in real dollars. Moving the odds 5 percentage points requires $1,830 for December 31 and $2,378 for April 30, making both markets relatively stable given the subject matter.

With Trump’s war-making authority unchecked by Congress, the path to further escalation stays open. Buying YES at 8¢ pays $1 if Congress declares war, a 12.5x return. That bet requires belief in a formal declaration within the next 259 days.

Watch for Trump’s next actions and statements on Iran, Congressional Committee moves toward authorization, or diplomatic developments. Any sign of bipartisan support for military action or a White House request for a war declaration could move this market fast.

Get prediction market intelligence as a structured API feed. Early access waitlist.