A major branch of the US military does not have a Senate confirmed leader for the first time in more than a century, as a result of a Republican senator refusing to lift his block on military nominations.

Commandant of the Marine Corps Gen. David Berger relinquished command on Monday after holding a private retirement ceremony, after more than 40 years of service. His successor, Gen. Eric Smith, has not yet been confirmed to take over due to the hold on senior military nominations by Alabama Sen. Tommy Tuberville.

Speaking at Berger’s relinquishment of command ceremony on Monday, Defense Secretary Lloyd Austin made a point to mention the hold and its impact on “stable and orderly leadership transitions,” and military families.

“We have a sacred duty to do right by those who volunteer to wear the cloth of our nation,” Austin said. “And I remain confident that all Americans can come together to agree on that basic obligation to those who keep us safe. I am also confident that the United States Senate will meet its responsibilities. And I look forward to welcoming an outstanding new commandant for our Marine Corps, and to adding many other distinguished senior leaders across the joint force.”