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James Mattis was "dismissed as a warmonger during the Obama administration," notes a Monday New York Times profile of the defense secretary, but in President Trump's Washington he is hailed as a bastion of stability and keeper of the status quo.

With former Secretary of State Rex Tillerson — whom the Times reports Mattis dubbed "St. Rex" for his treatment by Trump — Mattis has been cast as a bulwark to keep the president's more reckless impulses in check. Now, with Tillerson set to be replaced by Mike Pompeo and the appointment of arch-hawk John Bolton as national security adviser, Mattis is likely the sole significant administration voice pushing for any degree of foreign policy restraint, particularly where North Korea is concerned.

Mattis has reportedly indicated he does not expect to work well with Bolton, who has long argued for a preventive strike against North Korea as well as Iran. "This gets to a fundamental question," a "retired senior officer" who is close to Mattis told the Times: "Can Mattis win the president over [on North Korea], the most important debate we've had in decades, maybe centuries? I believe there is a moral hazard with this president, he will take everybody to the cliff," the source added. "If Mattis is able to prevail, that is what God put him on Earth to do. It's that serious."

Read the full New York Times report here.