The Polymarket contract for a formal US declaration of war on Iran by December 31 sits at 7.5% YES, down from 8% a week ago, even as US-Israel-Iran tensions persist.
Market reaction
The US declaration of war by April 30 contract is priced at 0.7% YES, unchanged over the week. The seven-point gap between the April 30 and December 31 contracts suggests traders expect any escalation to play out over a longer time frame, with a possible catalyst later in the year.
The December 31 market trades at $21 in daily face value, with $2 in actual USDC volume. The April 30 market sees $38,171 in face value and $327 in actual USDC, showing more speculative activity despite the lower odds. It takes roughly $2,378 to move the April 30 contract five points, a thin order book.
Why it matters
A formal Congressional declaration of war against Iran would be the first such declaration since World War II. The low but nonzero odds reflect real uncertainty about whether the current conflict trajectory could produce that outcome within 259 days. Buying YES at 7.5¢ pays $1 if Congress declares war, a 13.3x return.
What to watch
Congressional activity is the direct trigger here: any scheduled votes or formal requests for a war declaration would move these contracts fast. Secretary of Defense Pete Hegseth’s briefings and changes in US military posture in the Persian Gulf are the most likely precursors to such a move.
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Term Structure| Contract | Odds | Δ since publish | Volume 24h | |
|---|---|---|---|---|
| December 31, 2026 | 7.5% | — | — | Trade → |
| April 30, 2026 | 0.5% | — | — | Trade → |
