Why is Mattis still there, and for how long?

Trump is said to divide the members of his Cabinet into first-tier “killers” and second-tier “winners.” Mattis is indisputably a killer, but he’s also something rarer: a sometime loser — of policy arguments, that is — who manages to disagree with the president without squandering his clout or getting under Trump’s skin. He opposed Trump’s decision to withdraw from the Paris climate change accord, decertify the Iran deal, slap tariffs on steel and aluminum, and move the U.S. Embassy in Israel from Tel Aviv to Jerusalem. He opposes the president’s proposed ban on transgender service members and has reportedly ignored requests from the White House to see plans for a military strike against North Korea.

  Politico

But, importantly, he hasn't called Trump a fucking moron. That we know of.

One senior administration official called [Mattis] “bulletproof.”

Of the Cabinet selections and staff picks cheered by Trump critics, including McMaster, Kelly and former chairman of the National Economic Council Gary Cohn, Mattis is the only one who seems to still have job security. Trump remains as enthused about Mattis, one of his first Cabinet picks, as he was when he tapped him for the job in December 2016, according to several White House aides.

How would they know? He's such a liar.

[C]ritics say privately that Mattis is too cautious and conventional in his thinking, and that he doesn’t sufficiently appreciate the political nature of his current job. But “they regard him as better than the likely alternatives,” one such critic told me, and consider him “a restraining hand on an otherwise unpredictable and impulsive president.”

Oh, sure. Didn't we just read that for all the things Mattis opposed, Trump did what he wanted to anyway?

People close to the president sense that on a subset of important issues, he will defer to Mattis, who represents an institution, the military, that the president venerates, and whose status as a combat veteran has earned him Trump’s respect.

So, those people - what's their excuse for him firing McMaster?

Mattis benefits from serving a president who has never claimed to understand the military or international affairs.

Okay, is this those people or is this the reporter, because that is demonstrably false.

Running Central Command under Obama, Mattis learned that presidents are particularly sensitive to what military leaders say about them. If watching McChrystal defenestrated didn’t drive that home, his own experience did when, in 2013, he was ousted by the president for what the White House perceived as his outspoken hostility to the administration’s diplomatic overtures to Iran. Mattis’ frank remarks cost him access and, ultimately, his job.

[...]

In the Trump administration, where the president judges his Cabinet officials in large part based on the coverage they generate on television, Mattis has navigated the news media more deftly. He has appeared on just one Sunday morning news show during his time in office and rarely appears behind the lectern at the Pentagon. He seems to take pains never to overshadow the president.

[...]

“You won’t ever hear Mattis quoted off the record saying Trump is dumb or an idiot — he’s careful,” said Perry, the military historian.

And there you have it: that's why Mattis is still there. He's hawkish on Iran, Obama dumped him, and he doesn't upstage Trump.

Plus:

“Mattis has figured out how to play Trump perfectly. He keeps his head down and keeps his face out of the news,” says Tom Ricks, a columnist for the military news site Task & Purpose and the author of several books on military affairs. Mattis, said Ricks, is a “natural-born killer,” and “Trump, just like dogs smell fear, I think somebody like Trump who has very little natural courage, just smells it.”

"Mad Dog" - Trump loves the sobriquet and the implication.

Appearing on Face the Nation last May, Mattis played the warrior when CBS News’ John Dickerson asked him, “What keeps you awake at night?”

“Nothing,” Mattis told him. “I keep other people awake at night.”

Trump wishes he'd said that.

The response delighted the president, who told several White House aides how much he liked it. In private, Mattis talks with the president the same way. “He’s said similar things several times,” said a former White House aide. “Trump loves it.”

Mattis channeled the same sentiment when he was asked, in early February, whether he had any misgivings about the president’s plans for a military parade. “I’m not paid for my feelings,” he replied. “I save those for my girlfriend.”

Oh! Another good one Trump wishes he could say.

Trump asked top-dollar Republican donors last September [...] what they thought of Mattis and bragged, “The guy never loses a battle, never loses. Winning record.”

Ummmm...he's no longer on the battlefield.

Visiting Trump at his golf club in Bedminster, New Jersey, the second weekend after he was elected, Mattis and the president-elect discussed how to conduct a war against ISIS, which Mattis made clear would “not be a war of attrition, it’s going to be a war of annihilation,” according to a source familiar with the discussion. “Trump couldn’t get enough of it,” this person says.

[...]

Mattis had his own unpleasant collision with the news media when he told a group of Marines at a 2005 event that it was, at times, “a hell of a lot of fun” to shoot people. Unbeknownst to him, cameras were rolling.

So, really, who's in the way of a war with Iran? Nobody.

...but hey, do what you want...you will anyway.