WASHINGTON — A divided House voted on Thursday to overturn a Pentagon policy guaranteeing abortion access to service members regardless of where they are stationed and to bar health services for transgender military personnel, imperiling passage of the annual defense bill as right-wing lawmakers rallied Republicans around their drive to load the measure with conservative policy dictates.

The vote was 221-213, nearly along party lines, to attach the abortion proposal to the bill, with Republicans propelling it to passage over near-unanimous Democratic opposition. It was one of a series of controversial amendments that hard-right lawmakers demanded be put on the floor as a condition for allowing the legislation to move forward.

By a vote of 222-211, the House also adopted a measure to bar the military’s health plan from covering gender-transition surgeries — which currently can be covered only with a waiver — and gender-affirming hormone therapy.

Democrats condemned the moves, with some warning Thursday that they could not support the defense bill with the abortion restriction included.

“The MAGA majority is using our defense bill to get one step closer to the only thing they really care about: a nationwide abortion ban,” Rep. Katherine M. Clark of Massachusetts, the Democratic whip, said in a floor speech.

Democratic support is seen as crucial for passing the defense bill in the narrowly split House, where Republicans have only a slim majority. The $886 billion measure would grant a 5.2% pay raise to military personnel, counter aggressive moves by China and Russia, and establish a special inspector general to oversee U.S. aid to Ukraine.

But Thursday, Democrats called the abortion measure unacceptable in the wake of the Supreme Court’s ruling last year overturning abortion rights, which set off a rush by some states to enact bans and curbs on the procedure. Rep. Mikie Sherrill, D-N.J., a Navy veteran, said the Republican provision “puts servicewomen and military families’ lives at risk by denying the basic right to travel for health care no longer available where they are stationed.”

Republicans defended the move as a matter of principle, arguing that the Pentagon policy it would overturn — offering time off and travel reimbursement to troops traveling out of state to obtain an abortion — violated a prohibition against taxpayer-funded abortions.

The debate unfolded after Speaker Kevin McCar thy capitulated this week to a small group of ultraconservative Republicans who had threatened to block the defense legislation if their proposals, including pulling U.S. aid to Ukraine, did not receive consideration.

Instead the House moved forward on Thursday, slogging through dozens of proposed modifications with the fate of the bill still in doubt.

It overwhelmingly defeated two Republican efforts to cut U.S. military assistance for Ukraine. The vote was 341-89 to reject a measure from Rep. Marjorie Taylor Greene, R-Ga., to end a $300 million program to train and equip Ukrainian soldiers, which has been in place for almost a decade. And by a vote of 358-70, the House rejected a proposal from Rep. Matt Gaetz, R-Fla., to prohibit sending any more security assistance to Ukraine. In both cases, the supporters were all Republicans.

Those results were a victory for mainstream Republicans, who have defended U.S. military assistance to Ukraine as vital to countering Russia. But they reflected how anti-Ukraine sentiment is growing in the Republican ranks. In the spring, only 57 Republicans voted against a $40 billion package of military and humanitarian assistance for Ukraine.

Though defense bill debates have often been a forum for partisan policy fights, the debate in the House has been particularly nasty, exposing Republican divisions and threatening the customary bipartisan consensus around the legislation. The measures that Republicans have proposed stand no chance of passing the Democratic-led Senate, and a protracted fight over the measure could imperil its chance of enactment.

Republican leaders, who can afford to lose no more than four votes on their side if Democrats remain united in opposition, had been counting on Democratic votes to help pass the defense bill. The demands of hard-right lawmakers to load the bill with a deeply conservative cultural agenda could cost them those critical votes.