The US Marine Corps is now without a permanent leader and other top officer nominations are being held up because of a single Republican senator's views on abortion.
Tommy Tuberville from Alabama is using a Senate procedure to put a hold on hundreds of military nominations from moving forward because he believes the Pentagon is improperly using government funding to cover travel costs for abortions for service members and their dependents.
The military is already having to shuffle staff to fill a top leadership post after the commandant of the US Marine Corps, Gen David Berger, stepped down on Monday when his four-year term ended.
His deputy has taken over in an acting capacity, but Mr Tuberville's hold on promotions has left the marines without a confirmed leader in the job for the first time in more than a century.
On Tuesday, President Joe Biden's nominee to become the next chairman of the Joint Chiefs of Staff, Gen Charles Brown, warned that Mr Tuberville's blockade of military promotions could have a far-reaching impact across the US armed forces, affecting troops and their families.
“We will lose talent,” Gen Brown, the departing Air Force Chief of Staff, told his Senate confirmation hearing to become the Pentagon's top officer.
An aide to Mr Tuberville said his block would also apply to Gen Brown.
Democrats including Senator Elizabeth Warren slammed Mr Tuberville for punishing uniformed military leaders who were not responsible for the policy on abortion travel that he was protesting against.
“If the senator from Alabama continues his reckless action, he will soon be holding 650 leaders who have served their country honourable hostage,” Ms Warren said.
Gen Brown would be only the second black officer to become chairman of the Joint Chiefs of Staff, after Colin Powell two decades ago.
Mr Tuberville has also drawn criticism after he said white nationalists were simply “Americans”.
In a speech on the Senate floor, Senate Majority Leader Chuck Schumer, a Democrat, said the Republican was “on a one-man mission to excuse and even defend the meaning of white nationalism”.