We emphatically do not want high-ranking military service to become a tacit prerequisite for civilian leadership posts over the Department of Defense."

In the run-up to his confirmation vote, Austin has worked to overcome objections from some lawmakers to allowing a recently retired general to assume the top civilian post at the Pentagon.

He addressed those concerns directly at a Senate Armed Services Committee hearing Tuesday afternoon, saying, "If confirmed, I will carry out the mission of the Department of Defense, always with the goal to deter war and ensure our nation's security, and I will uphold the principle of civilian control of the military, as intended."

"I understand and respect the reservations some of you have expressed about having another recently retired general at the head of the Department of Defense," he said at the hearing.

"The safety and security of our democracy demands competent civilian control of our armed forces, the subordination of military power to the civil."

This story and headline have been updated to reflect additional developments Friday.