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

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.