WASHINGTON — At 3:04 PM on Monday the Senate received President Trump’s formal nomination of Mark Esper to be secretary of defense. At that time, Esper ceased to serve as acting secretary of defense and is solely serving as secretary of the Army.

As directed by Executive Order 13533 issued in March 2010, “Providing an Order of Succession Within the Department of Defense,” Secretary of the Navy Richard Spencer became acting secretary of defense.

“As such, Secretary Spencer has the full authority and responsibility of the Secretary of Defense,” Pentagon spokesman Jonathan Hoffman said in a statement.

Spencer will be acting defense secretary until Esper is confirmed. The Senate Armed Services Committee will consider his nomination in a hearing scheduled for Tuesday July 16.

Spencer on July 15 became the third acting Pentagon chief this year following the resignation of Jim Mattis December 31. Mattis’ deputy Patrick Shanahan moved up to acting secretary and was poised to be nominated until he abruptly resigned June 18 due to family issues. Esper became acting defense secretary June 24. This is the longest period in Defense Department history that the agency has been without a Senate-confirmed leader.

“The senior team supporting the Office of the Secretary remains in place to ensure institutional continuity,” Hoffman said in the statement. David Norquist, the undersecretary of defense (comptroller) and chief financial officer continues to perform the duties of deputy secretary of defense.

Thomas Modly, the undersecretary of the Navy, is now performing the duties of the Secretary of the Navy. Ryan McCarthy, who had moved up to acting Army secretary when Esper became acting defense secretary, is no longer performing the duties of the secretary of the Army and is solely serving as undersecretary of the Army.

In a letter addressed to all DoD and military personnel, Spencer wrote:

“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.”

According to a press pool report, Spencer on Monday walked into the defense secretary’s office and said: ”Ladies and gentleman, how are we doing today?”

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...