Will the US officially declare war on Iran by...?

What you need to know

This market asks one very specific question: will the US Congress pass a formal, official declaration of war against Iran — the kind last used in World War II — before the end of 2026? It is not asking whether the US and Iran will fight, trade strikes, or escalate tensions. Those things could all happen without this resolving Yes. A Yes means Congress votes, the president signs it, and the US is legally, constitutionally 'at war' with Iran. A No means anything short of that exact step. To settle as Yes, the US Congress must pass a formal declaration of war against Iran — a specific act of law under Article I, Section 8 of the Constitution — and the president must sign it, all before December 31, 2026 at 11:59 PM ET. Critically, this is a very high bar: military strikes, naval blockades, presidential orders, and even broad 'authorizations to use military force' do not count. Only the full constitutional declaration — something the US has not done since 1942 — qualifies. The news from July 14, 2026 is significant: the US has reportedly struck Iran, announced a naval blockade, and urged ships to leave Iranian ports, while the Strait of Hormuz has seen active fighting that killed an Indian sailor. This is a serious military escalation. However, for this market, what matters is not whether fighting is happening — it clearly is — but whether Congress takes the rare, formal step of declaring war, which is a separate political and legal act. The market sits at 5%, meaning participants see formal war declaration as very unlikely even amid active conflict. That reflects a real historical pattern: the US has fought many wars — Korea, Vietnam, Iraq, Afghanistan — without ever formally declaring war since 1942. The main uncertainty is not whether the two sides are 'close enough' to war; it's whether Congress would break an 80-year norm and take that specific legal step. The genuine unknown is whether the current escalation could force Congress's hand in an unprecedented way.

The odds right now

• December 31-1.0 pts (1w)5%

Price history

How this resolves

Resolves December 31, 2026

This market will resolve to "Yes" if the United States formally declares war on Iran through an act of Congress between market creation and the specified date, 11:59 PM ET. Otherwise, this market will resolve to "No." To qualify, Congress must pass a formal declaration of war, consistent with its constitutional authority under Article I, Section 8. Authorizations for the use of military force (AUMFs), executive orders, presidential statements, or military actions do not qualify unless accompanied by a formal declaration of war enacted by Congress and signed into law. The resolution source will be a clear consensus of credible reporting.

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