WASHINGTON >> A lone Senate Republican’s bid to reverse a Pentagon policy ensuring abortion access for service members is delaying the smooth transfer of power at the highest echelons of the armed forces, including in the ranks of the Joint Chiefs of Staff, as a monthslong partisan dispute over social policy drags on.

Sen. Tommy Tuberville, a conservative from Alabama, has been single-handedly blocking hundreds of promotions for high-ranking generals and admirals since February, refusing to relent unless the Defense Department scraps a policy — instituted after the Supreme Court struck down the constitutional right to abortion last year — offering time off and travel reimbursement to service members who need to go out of state for abortions.

Now, Tuberville’s tactics are on the brink of disrupting the Pentagon’s ability to fill its top ranks. More than half of the current Joint Chiefs are expected to step down from their posts during the next few months without a Senate-approved successor in place, leaving the president’s chief military advisory body in an unprecedented state of flux at a time of escalating tensions with China and Russia.

The Biden administration and Senate Democrats have vociferously condemned Tuberville’s blockade as dangerous and misplaced. But while many Republicans are deeply uncomfortable with his tactics, GOP leaders’ criticism has been more restrained.

“I don’t support putting a hold on military nominations,” Senate Minority Leader Mitch McConnell, R-Ky., told reporters recently when asked about Tuberville’s actions. That has not been enough to dissuade the Alabama senator or his staunch supporters in the GOP ranks, who have stood in for him when he was not at the Capitol to press his objections to a policy that has angered the anti-abortion Republican base.

The resulting impasse is beginning to take a tangible toll on the military. Today, the first of the departing Joint Chiefs, Gen. David Berger, the Marine commandant, will retire in a “relinquishment of office” ceremony, leaving his current deputy and nominated successor, Gen. Eric Smith, to take over without Congress’ blessing.

Over August and September, the staff chiefs of the Army, the Navy and the Air Force, as well as Gen. Mark Milley, chair of the Joint Chiefs, are expected to follow suit, leaving the organization with more temporary occupants than at any point in its history.

“We know that these holds are going to have a ripple effect throughout the department,” Sabrina Singh, a Pentagon spokesperson, said last month, arguing that Tuberville was setting “a dangerous precedent” that “puts our military readiness at risk.”

Similar sentiments have been voiced by the White House, where press secretary Karine Jean-Pierre argued last month that Tuberville’s tactics were “a threat to our national security,” and by Senate Majority Leader Chuck Schumer, D-N.Y., who denounced on the floor last month “the damaging impact that Sen. Tuberville’s holds on senior military promotions is having on our national security and military readiness.”

Even some Senate Republicans who have stopped short of condemning Tuberville’s actions have nonetheless expressed concerns about how they might affect the military’s ability to respond to global threats.

“It’s a dangerous world right now, and we want to make sure that we’re not sacrificing readiness,” Sen. Bill Cassidy, R-La., recently told Politico.

Some caution that such concerns are overblown.

Tuberville’s blockade “does not endanger the United States, but it makes the institutions less agile and adaptive,” said Mark Cancian, a retired colonel from the Marine Forces Reserve and a defense expert at the Center for Strategic and International Studies. Referring to officials who are serving in an acting capacity, he said: “When you’re acting, you cannot give fundamental strategic guidance to the institution. You are a place holder.”

Tuberville rejects the notion that his objections will have a detrimental effect on the military, noting that in situations where a single senator denies the customary unanimous approval of a group of nominations or military promotions, the Senate can simply schedule individual votes on each one.

“There’s all this panic about, ‘Well, he’s not going to give unanimous consent to the chairman of the Joint Chiefs,’” Tuberville’s spokesperson, Steven Stafford, said in an interview last week, pointing out that senators took a roll-call vote to confirm Milley as chair of the Joint Chiefs of Staff four years ago. “Maybe it’s OK for the Senate to take votes.”

But that process can be extraordinarily time-consuming given the Senate’s rules and customs, and trying to confirm each of the hundreds of promotions individually could tie the chamber in knots. That may be the point for Tuberville, who has co-sponsored legislation to declare that life begins at conception and filed a brief in support of the Mississippi law prohibiting abortion at 15 weeks that was upheld in last year’s Supreme Court decision in Dobbs v. Jackson Women’s Health Organization.

Senate Democrats have challenged Tuberville at least a half-dozen times on the Senate floor to stop holding military promotions hostage, and the Armed Services Committee has continued to hold confirmation hearings for high-ranking nominees, in the hopes that the Alabama senator might relent. Gen. Charles Brown, the Air Force chief of staff and President Joe Biden’s pick to succeed Milley as chair of the Joint Chiefs, and Gen. Randy George, the Army’s vice chief of staff whom Biden nominated to take over as Army chief, are both scheduled for hearings this week.

But their efforts have thus far failed to dissuade Tuberville, who has dismissed his critics by arguing that Senate leaders have options to resolve the impasse. He has suggested that Congress pass Republican-sponsored legislation to reverse the Pentagon’s abortion access policy — or a competing Democratic bill to give the policy the force of law. He has dared Senate leaders to circumvent his blockade by voting on the promotions individually, arguing that he would be ready to approve some promotions if forced to take a vote.

But Senate aides say none of his suggested offramps are workable. Senate leaders believe it would be nearly impossible to collect enough votes, between the Democratic-led Senate and the Republican-led House, to send legislation either affirming or overturning the Pentagon’s policy to the president’s desk. And they are queasy about trying to get around Tuberville’s protest procedurally because of the amount of time it would take to plow through the Senate’s arcane hurdles for all the nominations he is holding up.

Senate leaders are also resisting pressure from rank-and-file lawmakers to make an exception for the Joint Chiefs, fearing that doing so would legitimize Tuberville’s protest — and encourage others harboring grievances with Pentagon policies to emulate his approach.

In the meantime, Tuberville has steadily rejected compromises that Senate leaders have offered. He refused to relent in exchange for holding a closed-door vote in the Armed Services Committee last month against a bill undoing the Pentagon’s policy. And he has publicly eschewed the idea of settling his dispute by voting on the Pentagon’s policy as an amendment to the annual defense policy bill, which is expected to begin moving through the House next week.

Senate leaders hope to change Tuberville’s mind over the next few weeks.

Challenges to the Pentagon’s abortion access policy are expected to figure in the House debate on the defense authorization bill. Republicans have filed two proposals — one of them with more than 50 co-sponsors — to bar the Defense Department from using federal funds to reimburse any abortion-related expenses, which would effectively undo the Pentagon’s policy. A group of House Democrats has filed a competing proposal seeking to make the Pentagon’s reimbursement policy a requirement of federal law.

Even if either of those changes were made to the House bill, it would still face significant hurdles in the Senate — particularly since aides in both parties fear that if the must-pass defense bill is seen as a Trojan horse for abortion measures, lawmakers will vote against it in droves. But they hope that such a public referendum on the Pentagon’s policy would back Tuberville into a corner, creating public pressure on him to give up his quest.

It is not clear how much difference that will make to him, however. Though Tuberville has few backers in the Senate, he has been buoyed in his resistance by support from home, where constituents have cheered on his protest, and billboards paid for by the conservative Heritage Foundation line stretches of highway.

They read, “Senator Tuberville, thank you for standing for life, and against wokeness in the military.”

This article originally appeared in The New York Times.