Losing Mattis would be costly for Trump

President Trump has clearly soured on Defense Secretary Jim Mattis, and top Republicans and Democrats both tell me his departure would be particularly costly for the White House — and a disturbing sign for outsiders.

The big picture: A former aide who can read Trump like a book told me: "His tone on Mattis is really striking. ... Will be worth watching whether he's just brushing him back and moving on, or if he launches a sustained effort to get him to quit." And if Mattis departs on anything other than the most cordial terms, confirming a successor will be fraught.

But here's something aides may not have told the president: People who know Mattis tell me that he won't stay around to be abused and humiliated like Attorney General Jeff Sessions has.

• If "Mad Dog" Mattis, as Trump calls him, is convinced that the president is shorting his stock, the retired four-star Marine general could leave abruptly.

After recent rumblings of frayed relations with Mattis, Trump's comments on "60 Minutes" last night sent a signal to the world — including allies who depend on the U.S. for their defense — that the Pentagon chief may be a short-timer.

• Based on an early clip from CBS News, we told you yesterday about Trump's devastating remark to correspondent Lesley Stahl that Mattis is "sort of a Democrat, if you wanna know the truth. ... He may leave."

But it turns out there was more:

• Stahl: "Is it true General Mattis said to you, 'The reason for NATO and the reason for all these alliances is to prevent World War III?'"
• Trump: "No, it's not true. ... Frankly, I like General Mattis. I think I know more about it than he does. And I know more about it from the standpoint of fairness, that I can tell you."
• Stahl: "I'm gonna try one more time."
• Trump: "Lesley, you don't have to try again. I know exactly what you're saying. ... I will always be there with NATO, but they have to pay their way. I'm fully in favor of NATO, but I don't wanna be taken advantage of."

Be smart: Mattis is a linchpin of what we call the Committee to Save America — an unofficial alliance of officials who see it as their patriotic duty to protect Trump and the nation from disaster.

• When I asked a well-wired Democrat how worrisome Mattis' departure would be, he replied: "Number one by far. Super scary."