President Trump and acting defense secretary Patrick Shanahan at a Cabinet meeting early this month. (Jim Young/Reuters)

With the cameras switched off and recording devices scattered in front of him, Patrick Shanahan made his debut in the Pentagon briefing room Tuesday as acting defense secretary, conducting the first public news conference of what could be years of CEO-style leadership or a short stint as a stand-in before the appointment of a permanent replacement. 

Shanahan, a longtime Boeing executive who served as deputy to Defense Secretary Jim Mattis for some 18 months, is essentially in tryouts. His unusually public audition to join President Trump’s Cabinet on a permanent basis has brought a new air of caution to the Pentagon and at least temporarily reduced the public profile of a Defense Department boosted for two years by Mattis’s stature.  

Sitting at a desk instead of standing at a lectern, Shanahan could not say for sure Tuesday whether he would be staying in his job, acknowledging that his mother sends him prayer emoji. His staff continued Mattis’s tactic of avoiding televised briefings, lest the president see something he doesn’t like, but Shanahan joked that his mother would like to see more of him on television. The short answer to the question of his fate: He will stay or go as told.

“It’s really whatever the president or the country would like me to do,” he said. “That’s what I’m prepared to do.” 

Whether Shanahan, 56, can serve in an acting capacity indefinitely, without nomination and confirmation in the Senate, is a matter of some debate. Trump has said he likes keeping officials in acting status because it gives him more flexibility. The president has heaped praise on Shanahan, saying on Twitter that he is doing a great job and describing him as fantastic in a speech at the Pentagon. Trump has said Shanahan could remain in the Pentagon’s top job “for a long time.”

In some respects, Shanahan is everything Mattis is not. Despite at one point serving as general manager of Boeing’s missile defense program, he is largely an outsider in Washington, while Mattis spent his entire professional life in the military.

Whereas Shanahan prides himself on being a student of business, Mattis made his name as a student of war, leading troops in combat and crafting views on alliances, military training and battlefield strategy during four decades in the Marine Corps. Known as the “Warrior Monk,” Mattis prided himself on being an ideas man; Shanahan, after more than three decades at Boeing, emphasizes streamlining processes and better execution. Mattis came into the Pentagon with a vaunted public profile and long-standing relationships on Capitol Hill; Shanahan remains largely unknown to the public and owes his Washington career to Trump.

Despite their differences, Shanahan began his briefing Tuesday by saying he would chart the same course that Mattis set for the Pentagon. Mattis’s primary priorities were to reorient the military toward great-power competition with Russia and China, bolster alliances across the globe and build what he regularly described as a more “lethal” fighting force. 

“No change to the priorities,” Shanahan said. “No change to the strategy. It’s really, ‘Go faster on the implementation and execution.’ ”

Before his resignation over differences with Trump, Mattis focused intently on developments facing U.S. forces overseas and crafted a hectic travel schedule to visit foreign nations and leaders. He was as much a force in foreign policy as his counterparts at the State Department.

Shanahan, who has relatively little formal foreign policy experience, signaled a more inward focus Tuesday, noting that he would not be traveling as much and would concentrate on closing the “seams” he had noticed in the organization of the Defense Department in his time as Mattis’s No. 2.

In his first month on the job, Shanahan has been working on many of the same issues that occupied him while deputy secretary. He rolled out the Pentagon’s new missile defense strategy, which he had worked on previously, and will soon unveil the department’s budget request for the 2020 fiscal year, which he has described as a “masterpiece” and evidence of the military’s move away from counterinsurgency toward great-power competition. Shanahan also served as the point person for Trump’s Space Force in his previous job and signaled Tuesday that he would continue that focus.

Unlike Mattis — whom allies often viewed as a counterpoint to Trump willing to stand up for traditional American foreign policy values — Shanahan has crafted an image of a loyal corporate-style foot soldier, particularly during his oversight of the Space Force plan.

Asked whether he would tell Trump that it is inappropriate for a president to deliver partisan political jabs during speeches to military personnel — as Trump did at the Pentagon this month and at a base in Iraq in December — Shanahan said he is always ready to give the president feedback.

It has been a long-standing responsibility of the Defense Department not to politicize the military, Shanahan said, pledging to work to keep a nonpolitical environment at the Pentagon.

“Why that is so important is that we recruit from all parts of the United States,” Shanahan said. “This is an all-volunteer force.”

Whether Shanahan becomes a leading force within the Trump administration on foreign policy decisions remains to be seen. On Tuesday, he largely deferred questions about progress on a peace deal with the Taliban in Afghanistan to the State Department.

Though the Pentagon usually draws up options for possible military action and sends them to the White House, Shanahan suggested that White House national security adviser John Bolton was taking the lead on Venezuela policy and had created a “number of options” on what to do there.

“We support them with their policy development, and as the situation in Venezuela evolves we are there to give them advice and counsel and support,” Shanahan said. He said he had not talked to Bolton about the possibility of sending 5,000 troops to neighboring Colombia, as a note the national security adviser displayed for the cameras at a White House briefing this week suggested. 

As a former business executive, Shanahan speaks Trump’s language, sharing his aim to cut better deals on high-profile acquisitions, such as the F-35 fighter jet. 

Shanahan dismissed suggestions that he had been biased toward Boeing during his time as deputy secretary by expressing dismay about the F-35, made by Boeing competitor Lockheed Martin. He signed an ethics agreement recusing himself from Boeing matters before the Pentagon and called allegations on the matter “just noise.” 

“I am biased towards performance. I am biased towards giving the taxpayer their money’s worth,” he said. “And the F-35, unequivocally, I can say, has a lot of opportunity for more performance.”