MARY LOUISE KELLY, HOST:
Today marks 77 days for Patrick Shanahan as acting secretary of defense. Shanahan is just the third acting Pentagon chief ever. As of today, he is also the longest-serving one. Despite much speculation that President Trump would nominate Shanahan to fill the role permanently, that has not yet happened. And it's not clear why it's taking so long to fill what is arguably the most consequential post in Trump's Cabinet. NPR national security correspondent David Welna is here to reveal all - no pressure, David.
DAVID WELNA, BYLINE: All right.
KELLY: Welcome. So start with why this matters. Why does it better that the Pentagon is being run by an acting defense secretary?
WELNA: Well, you know, as with any top executive job, if you're there only in an acting position, nobody really knows how much to bank on what you say. The defense secretary really is the public face of the Pentagon to the world. And Shanahan met today, for example, with France's defense minister. So both allies and adversaries may be left wondering how much longer this guy is going to have this job.
And beyond that, Shanahan spent most of his career at Boeing. So his experience in military matters is strikingly limited. He's seen more as a manager than a strategist at a time when some pretty big rethinking of the Pentagon's mission is being called for in the national defense strategy, especially when it comes to conflicts with great power rivals, namely Russia and China.
KELLY: Jim Mattis, who of course was the last confirmed defense secretary and who quit in December - I'm remembering that in his resignation letter, Mattis wrote to the president, you have the right to have a defense secretary whose views are better aligned with yours. Does Shanahan fit that job description?
WELNA: Well, Shanahan has at least publicly largely shown himself to be a yes man with the president, something Trump did not always have with Mattis. At his first Cabinet meeting as acting defense secretary, here's what Shanahan had to say about the situation on the border with Mexico as he was sitting there right next to Trump.
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PATRICK SHANAHAN: The threat is real. The risks are real. We need to control our borders.
WELNA: But at a Senate Armed Services Committee hearing last week, Hawaii Democrat Mazie Hirono pointed out that the general who heads the U.S. Northern Command who oversees the border recently told the panel the situation along the southern border was not a military threat. And she asked Shanahan if he agreed. Here's what he had to say about that general's assessment.
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SHANAHAN: He said border security is national security.
MAZIE HIRONO: I understand that, but he said specifically that it's not a military threat. And I'm asking you whether you agree with him that it's not a military threat.
SHANAHAN: I agree with him.
WELNA: On Friday, the day after Shanahan said that, Trump went out to the Pentagon. And the expectation was that he'd announced there that he was nominating Shanahan to be defense secretary. But of course that didn't happen.
WELNA: Not clear if Shanahan's somewhat halting performance in front of the same Senate panel that would consider such a nomination had anything to do with that.
KELLY: Well, so what does this tell us about Shanahan's prospects for being nominated for the permanent job?
WELNA: Well, by all reports, Trump likes Shanahan. But he also told reporters when Shanahan had only been on the job for a few days that he was in no hurry to find a new defense secretary, saying he sort of liked acting because it gave him more flexibility. And some of the people mentioned as possible replacements for Maddox, among them retired general Jack Keane and South Carolina Republican Lindsey Graham, have said they're not interested. So it could be that, A, Trump simply cannot find anyone to do the job and/or, B, he's watching to see how Shanahan works out
KELLY: OK, so the president says he's not in a hurry. But are there any limits on this? I mean, how long can Shanahan stay on in an acting capacity?
WELNA: It's not clear. There's a federal law that sets a limit of 300 days for acting secretaries. For Shanahan, that would mean no longer than late October. But there's another law specific to the Defense Department, and it says that if the secretary of defense post becomes vacant, then the deputy secretary of defense, the job Shanahan held when Mattis quit...
WELNA: ...Will then exercise the full powers of defense secretary. And it does not stipulate a time limit for doing so. So some legal scholars think this law trumps the 300-day limit. And that may only be cleared up if there's a legal challenge to Shanahan staying on as acting secretary.
KELLY: All right, NPR's permanent national security correspondent David Welna there. Thanks, David.
WELNA: You're welcome. Transcript provided by NPR, Copyright NPR.