In a 63-37 vote on Wednesday, the Senate agreed to a full floor debate of a bill challenging the legality of the US involvement in the Yemen War. The legal challenge is built around Congress never having authorized the US to join such a war.

Wednesday’s pre-vote efforts saw Secretaries of State and Defense Mike Pompeo and James Mattis taking senators into a closed-door, classified briefing that was aimed to cover both the Yemen War, and mounting concerns about the US relationship with Saudi Arabia.

All indications are that the briefing failed, with Sen. Chris Coons (D-DE) coming out of the briefing saying he was now opposed to the war. Sen. Bob Menendez (D-NJ), a former supporter of the war, has also changed sides, as have several others. Sen. Jack Reed (D-RI) has also said he supports the bill to end the war.

This mounting Senate support suggests the bill itself is very likely to pass, although it may ultimately stall in the House of Representatives, where a recent effort at a War Powers Act challenge to the war was derailed in favor of a wolf-hunting measure.