The Senate is set to break with the administration's support for the Saudi-led military campaign in Yemen on Wednesday, likely handinghis second setback from Capitol Hill this week."The resolution we will vote on in the Senate tomorrow to end U.S. support for the Saudi-led war in Yemen is enormously important and historic. This war is both a humanitarian and a strategic disaster, and Congress has the opportunity to end it," Sen.(I-Vt.) said in a statement.

Three Senate aides told The Hill that they expect a resolution to come to the floor Wednesday that will call on Trump to withdraw any troops in or affecting Yemen within 30 days unless they are fighting al Qaeda.

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The resolution would need only a simple majority to pass the Senate, which approved a similar resolution in December. The resolution would need to pass the House before heading to Trump's desk, where he has said he would veto the measure.

With Republicans holding 53 seats in the Senate, Democrats would need to win over at least four Republicans and keep their entire caucus united in order to pass the resolution. The 2018 resolution passed with 56 votes.

"It's going to be tight," he said late last week. "But you know nothing has happened to peel Republicans away."

—Updated at 5:56 p.m.