When President Donald Trump and his national security team make decisions soon about North Korea and Iran that could eventually lead to war, one of the few voices of restraint in the room may be a man known as “Mad Dog.”

That nickname has never quite fit that man, Defense Secretary James Mattis, and he doesn’t like it. Mattis is a fierce warrior, but war to him is a last resort, because he has seen firsthand its horrible toll.

Much the same can be said for two other Marines whose counsel to Trump will be critical in the days ahead: Gen. Joseph F. Dunford Jr., chairman of the Joint Chiefs of Staff, and White House Chief of Staff John F. Kelly, who also wore four stars.

But these voices of relative reason in the Trump administration are fewer now. The latest casualty is H.R. McMaster, an Army three-star general who was national security adviser. Trump announced Thursday he is replacing McMaster with John Bolton, the former U.S. ambassador to the United Nations in the George W. Bush administration, who later became a TV pundit and a raiser of campaign cash for conservatives.

Bolton is one of the most hawkish voices in America. To some, that’s just what is needed in a troubled world. And tough talk has its place. It’s arguable that North Korea would not have considered talking to the United States had Trump not made the U.S. military threat seem more credible through his often bellicose — and, yes, frightening — tweets.