More on Mattis resignation

The defense secretary delivered his resignation letter after what one senior administration official described as a disagreement in the Oval Office on Thursday afternoon, during which Mattis sought to convince the president to stand down with the Syria withdrawal but was rejected.

By then, the president had shocked the Pentagon by filming a video on the White House lawn claiming the Islamic State had been defeated and American troops would be coming home.

Mattis also has argued against removing troops from Afghanistan, which Trump is leaning toward doing in the coming months.

  WaPo

And perhaps because Mattis dared to resign in an unflaterring letter.

The final rupture between the defense secretary and the president came after weeks of tensions over Trump’s broadsides against allies, his demands to withdraw from military entanglements in the Middle East and personnel decisions.

The defense secretary lost the most crucial battle on that front this month when the president disregarded his recommendation to make Air Force Chief of Staff Gen. David Goldfein the next chairman of the Joint Chiefs of Staff and instead chose Army Chief of Staff Gen. Mark A. Milley.

A person close to Mattis said that proved particularly offensive to him.

“It’s the one major selection the secretary of defense usually gets. And the president totally overruled him,” the person said.

In the weeks leading up to that moment, Trump publicly called Mattis “sort of a Democrat” and began referring to the retired general as “Moderate Dog.”

[...]

Mattis expressed skepticism over the prospects of nuclear disarmament negotiations with North Korea and bristled at the president’s decision to suspend certain military exercises as a goodwill gesture. Trump told advisers that he trusted Secretary of State Mike Pompeo, who has led the North Korea negotiations, more than he trusted Mattis.

Mattis also disliked the president’s conciliatory posture toward Russian President Vladi­mir Putin and emphasized in his resignation letter that Russia and China want to shape the world consistent with their authoritarian models.

[...]

Long seen as a bulwark against Trump’s isolationist and extreme impulses, Mattis was seen as a the “reassurer-in-chief” as the president sent out startling and provocative tweets. The retired general’s departure adds new uncertainty about which course the administration might take on its global challenge.

Several possible replacements for Mattis this week trashed the president’s decision to pull out of Syria. Retired Gen. Jack Keane called the move a “strategic mistake” on Twitter. Republican Sens. Lindsey O. Graham (R-S.C.) and Tom Cotton (R-Ark.) signed a letter demanding Trump reconsider the decision and warning that the withdrawal bolsters Iran and Russia.

[...]

But questions about Mattis’s influence grew as the president made decisions that deviated from his advice, such as pulling out of the nuclear deal with Iran, relocating the U.S. Embassy in Israel to Jerusalem and launching a new Space Force that many military leaders saw as unnecessary and distracting.

More recently, Trump ordered Mattis to send active duty troops to the U.S. border with Mexico, a move Democrats criticized as a political stunt that undermined the defense secretary’s goal of making the military more effective in responding to foreign threats.

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