WASHINGTON — A bipartisan trio of U.S. senators have introduced a measure aimed at ending U.S. military support for the the Saudi-led coalition in Yemen’s civil war.

Sens. Bernie Sanders, I-Vt.; Mike Lee, R-Utah, and Chris Murphy, D-Conn., introduced a joint resolution Wednesday to invoke the War Powers Act to overrule the president and withdraw troops from a conflict they believe is unauthorized.

“As Congress has not declared war or authorized military force in this conflict, the United States’ involvement in Yemen is unconstitutional and is unauthorized, and U.S. military support of the Saudi coalition must end,” Sanders said in a floor speech Thursday.

The resolution roughly matches one sponsored by Rep. Ro Khanna, D-Calif., which was denied a floor vote by House leadership.

“This is not a partisan issue. Support for the Saudi intervention in Yemen began under a Democratic president and has continued under a Republican one,” Sanders said. “Sen. Lee is a conservative Republican. I am a progressive independent who caucuses with the Democrats.”

U.S. troops refuel aircraft and provide targeting to the Saudi-led coalition fighting Houthi rebels in Yemen.

It’s unclear how U.S. troops will be impacted if the measure passes Congress and President Donald Trump signs it. A staffer for Lee said the Pentagon would implement the measure, adding that whether troops are moved would be up to military leaders.

“There’s no ‘how,’ ” the staffer said. “Either it happens after it gets the president’s signature, or it doesn’t happen.”

This is just the latest effort in Congress to debate the complicated security relationship between the U.S. and Saudi Arabia — a leading purchaser of American arms.

In June, the Senate approved a proposed arms sale to Saudi Arabia in a surprisingly narrow procedural vote, 53-47. In September of 2016, a vote to block another sale to Riyadh failed, 71-27.

The Saudi-led coalition, chiefly backed by the United Arab Emirates, backs Yemen’s internationally recognized government against Shiite rebels and their allies who are holding the Yemeni capital, Sanaa, and much of the north of the country.

The conflict is stalemated, however, and Saudi Arabia replaced its military chief of staff and other defense officials early Tuesday morning in a shake-up apparently aimed at overhauling its Defense Ministry.

The 3-year-old conflict has been a humanitarian crisis of historic proportions, and critics have said Washington’s support makes it culpable.

“Under this legislation, no longer would U.S. pilots serve as gas station attendants in the sky to refuel Saudi and UAE bombers that rein down terror on Yemeni men, women and children,” said Kate Gould, of the anti-war advocacy group Friends Committee on National Legislation.

More than 10,000 people have been killed in the conflict. The U.N. in recent days reported the Saudi-led coalition killed 68 children and wounded 36 others from July to September 2017. It welcomed the coalition’s announcement it would send $930 million to the U.N.’s humanitarian efforts.