US senators introduced bipartisan legislation on Wednesday to repeal decades-old authorizations for the use of military force used to justify years of attacks in the Middle East, an effort to shift back the authority to declare war to Congress from the White House.The measure, led by Democratic Senator Tim Kaine and Republican Senator Todd Young, would repeal 1991 and 2002 Authorizations for the Use of Military Force (AUMF) against Iraq, citing the "strong partnership" between Washington and the government in Baghdad.Under the Constitution, Congress, not the president, has the right to authorize war. But those AUMFs - and a third one, from 2001, for the fight against al Qaeda - have been used to justify strikes by both Democratic and Republican presidents since they were passed. They have been criticized as allowing "forever wars" that have kept U.S. forces fighting overseas for decades.The bill's introduction came a week after Democratic President Joe Biden's administration carried out air strikes against facilities belonging to Iranian-backed militia in Syria that renewed questions about whether a president should be able to conduct such actions without congressional approval.Tensions have been rising with Iran, after strikes in the region blamed on Tehran."Last week's airstrikes in Syria show that the Executive Branch, regardless of party, will continue to stretch its war powers," Kaine said in a statement. Members of Congress from both parties have sought repeatedly to repeal the AUMFs in recent years, but efforts have fallen short.The other sponsors of the new measure include Democratic Senators Tammy Duckworth, Chris Coons and Dick Durbin, as well as Republican Senators Mike Lee, Chuck Grassley and Rand Paul.