The leadership void in the US Army and the Marine Corps is widening over a political row in President Joe Biden’s administration, with the Pentagon warning that the impasse regarding top commander appointments may jeopardize the combat readiness of American troops.

The Pentagon raised the alarm after the months-long congressional dispute over hundreds of military promotions and nominations left both the US Army and Marine Corps without a top leader for the first time in US history.

Defense Secretary Lloyd Austin stressed that the US Senate’s failure to confirm military nominations for over 300 pending officer posts, including chiefs for the country’s two ground combat forces, is disruptive and could hinder relations with allies.

Austin said the impasse would potentially undermine efforts to recruit troops and ensure that they are ready to defend the nation.

“Today for the first time in the history of the Department of Defense, two of our services will be operating without Senate-confirmed leadership,” the Pentagon chief said in a speech at Joint Base Myer-Henderson Hall in Arlington, Virginia.

“In our dangerous world, the security of the United States demands orderly and prompt transitions of our confirmed military leaders,” he added.

The US Marine Corps has been without a top leader since General David Berger completed his four-year term as commandant on July 10. The void marked the first such leadership gap for the branch in 164 years.

The US Army was left with the same leadership void on Friday, when General James McConville relinquished his command as chief of staff.

Senator Tommy Tuberville, an Alabama Republican, has blocked approvals for the appointments in a dispute over the Pentagon’s new abortion benefits for service members and their dependents.

The impasse stems from the US Supreme Court’s decision last year to overturn Roe v Wade, a 1973 legal ruling that had protected abortion as a constitutional right. The reversal opened the door for dozens of Republican-led states to impose new restrictions on abortion.

US arms manufacturers received $9.7bn to fill empty caches after weapons given to Ukraine

American arms manufacturers reportedly received $9.7 billion to replace the weapons that were sent to Ukraine.

The Pentagon responded in February by ordering that all US military branches offer special benefits, including three weeks of paid leave and full reimbursement for expenses, to troops and family members who travel to abortion-friendly states to terminate pregnancies.

Using a procedural tactic, known as a hold to block confirmation, Tuberville has vowed to maintain the hold until the Pentagon repeals the policy or Congress enshrines it in law.

The Republican senator says his hold, which nears the six-month mark, is “NOT affecting national security” and has demanded that the Democrat-controlled Senate hold a vote on the abortion policy.

Biden has also called Tuberville’s blocking of nominations “irresponsible” and argued they jeopardize US security.

The US Democratic Senate leadership has resisted scheduling individual roll call votes, both because of the time-consuming process and for fear of emboldening senators to use the same tactic as Tuberville in the future.

Even if Democrats were inclined to hold roll call votes, the Senate is on its summer vacation, meaning the soonest they could hold the vote is September.