The Senate voted Wednesday by nearly two-to-one against an amendment from Sen. Rand Paul, R-Ky., to the defense authorization bill. The amendment would have ended the current Authorization for Use of Military Force within six months and forced Congress to vote on authorizing wars beyond that.

The authorization, which was passed in the immediate aftermath of the 9/11 attacks, is the legal justification for many U.S. military engagements abroad, as part of what has been called the “global war on terror.” The expansively interpreted law authorized military attacks against those responsible for 9/11 and “associated forces.”

The failed vote came after Paul took to the floor on Monday, vowing to block other Senate actions until his amendment was allowed.