Trump nominates Esper to be defense chief, replace Mattis

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 Tuesday and could be confirmed as early as Thursday. Spencer would then return to the Navy.

Esper took over as acting defense secretary in June when Patrick Shanahan abruptly quit after having served as acting secretary since Mattis departed. Thus Spencer, filling in for Esper as of Monday, is the third acting defense secretary this year.

Before the Trump administration, only twice before has the Defense Department been led by an acting secretary — most recently in 1989 — and never has it had more than one in a single year.

Esper, who has been the civilian leader of the Army since November 2017, has a wide range of experience with defense issues, including years on Capitol Hill. More recently he was a lobbyist for Raytheon Co., which does a lot of business with the Pentagon.