WASHINGTON -- President Donald Trump on Monday asked the Senate to confirm Mark Esper as the successor to former Defense Secretary Jim Mattis, whose resignation last December opened an unprecedented period of senior-level instability at the Pentagon.
The moment the nomination was received by the Senate on Monday afternoon, Esper was required to step out of his role as acting defense secretary -- a job he has held since June -- until he is confirmed as the permanent secretary. He reverted to his previous position of Army secretary.
Filling in for Esper pending his confirmation is Richard Spencer, who has been the civilian leader of the Navy since August 2017.
Spencer's tenure as acting secretary is expected to be brief. Esper will have his Senate confirmation hearing today and could be confirmed as early as Thursday. Spencer would then return to the Navy.
As soon as he took the handoff from Esper, Spencer sent a brief letter to all military and civilian personnel of the Defense Department.
"While my time in this role is anticipated to be brief, I am fully prepared and committed to serve as Acting Secretary of Defense, and I will provide continuity in the leadership of the department," Spencer said.
He said American allies and partners "can rest assured" that during this transition the Pentagon remains ready to meet its global commitments.
Spencer, a native of Connecticut, joined the Marine Corps after graduating from Rollins College in 1976. He served in the Marines until 1981 as an H-46 helicopter pilot, according to his official Navy biography.
He is a former Wall Street investment banker. For 10 years prior to becoming Navy secretary he was managing director of Fall Creek Management, a private investment firm.