President Trump said that he is “most likely” going to nominate Army Secretary Mark Esper to become the next secretary of defense, just hours after he tweeted that Esper would assume the role of acting defense secretary as Patrick Shanahan withdrew his name for consideration and announced he will resign from his role at the Pentagon.

Speaking to reporters June 18, Trump said nominating Esper “is what I am thinking of doing.”

Secretary of the Army Dr. Mark T. Esper attends an Army Full Honors Arrival Ceremony hosted by the Chief of Staff of the U.S. Army Gen. Mark A. Milley at Conmy Hall on Joint Base Myer-Henderson Hall, Arlington, Virginia, Jan. 5, 2018. Esper was recently appointed as the 23rd Secretary of the Army. (U.S. Army photo by Spc. Anna Pol)

Earlier in the media appearance, Trump called Esper “highly experienced” and added, “I think he’s going to fit in very easily,” according to a transcript provided Tuesday evening by the White House.

The Pentagon said Tuesday evening that Shanahan will resign from the Pentagon at midnight on June 23, with Esper taking over as acting defense secretary at 12:01 A.M. June 24.

“Acting Secretary Shanahan and Secretary of the Army Esper are committed to an orderly transition that ensures our men and women in uniform have the leadership and resources they need to keep our nation safe,” said Chief Pentagon Spokesman Jonathan Hoffman. David Norquist will continue in his role as performing the duties of the deputy secretary of defense, he added.

Trump first announced that Shanahan would withdraw his nomination for the defense secretary position via Twitter June 18, with Shanahan releasing his own statement shortly thereafter. Trump had announced his intent to nominate Shanahan as defense secretary in May, after assigning him to lead the Pentagon in an acting capacity following Jim Mattis’ resignation in December 2018.

Lawmakers said Tuesday that while they are confident in Esper’s capability to serve as acting defense secretary, they called on Trump to nominate a permanent pick as soon as possible to address growing threats from countries including Russia, China and Iran (Defense Daily, June 18).

Asked by reporters whether the lack of a permanent defense secretary complicates defense policy in areas such as Iran, Trump replied: “Frankly, this could happen very quickly for Mark Esper.  He’s very experienced. … He’s been around all of the things that we’re talking about for a very long period of time.”