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.

Still, the elevation of Bolton to Trump’s security consigliere carries major risks, to put it mildly.

National security advisers are supposed to present the president and his top aides with options from across the government on questions of defense, intelligence and diplomacy. They should share their candid views in the debate, but they are primarily brokers of it.

However, unless Bolton undergoes a major personality change, he is more likely to be an advocate than an arbiter. As a sharp-elbowed bureaucratic infighter, by multiple accounts, he may limit the options that the president sees.

Bolton will step into his job early next month at a pivotal moment in world history.

As Trump prepares for a potential meeting with North Korean leader Kim Jong Un as early as May, the new national security adviser will play a leading role in the planning sessions.

His views are already widely known, even if he said Thursday on Fox News that his past statements are “behind me.”

McMaster, like Mattis and Dunford, has called for the consideration of military options against North Korea and was clear that such a threat had to be held out even as the White House considered open and back-channel diplomatic avenues.

While Bolton has not explicitly said a military attack on North Korea should occur now, he has used code words to all but argue for that.

He recently suggested that in the upcoming talks with Kim, Trump should immediately call for Kim to give up his nuclear weapons and, if that didn’t work, Trump should start talking about “something else” — by which Bolton may very well have meant war.

It is not hard to imagine Trump saying something just like that to Kim.

Likewise, Bolton wrote in a Wall Street Journal op-ed just last month: “It is perfectly legitimate for the United States to respond to the current ‘necessity’ posed by North Korea’s nuclear weapons by striking first.”

“I think the only diplomatic option left is to end the regime in North Korea by effectively having the South take it over,” he said on Fox News last September.

To be sure, a limited U.S. or even South Korean strike might make Kim back down.

But don’t count on it. The more likely result of such an attack, experts say, is a war that could kill an unpredictably large number of people, perhaps millions — on the Korean peninsula, in Japan, or on U.S. bases on Guam and maybe even in America.

Watch: Trump’s Threat to North Korea in UN Address

Iran nuclear agreement

Then there’s Iran.

Bolton’s views can be summed up by the title of a New York Times op-ed he wrote in 2015, “To Stop Iran’s Bomb, Bomb Iran.”

“The inescapable conclusion is that Iran will not negotiate away its nuclear program,” he wrote in the piece, which appeared a few months before Iran agreed to pretty much do just that in the form of a temporary halt to its most worrisome atomic activities.

The administration will announce in mid-April whether it will unilaterally withdraw from that multinational deal, which U.S. intelligence leaders publicly say has frozen Iran’s nuclear progress.

Unlike McMaster, Mattis and Dunford, Bolton has said the Iran pact should be torn up and rewritten.

Such a move could lead to an improved agreement. But it is more likely, analysts worry, to embolden Iranian hard-liners and reignite their nuclear program, perhaps leading Saudi Arabia and others to follow suit.

Bolton is not against diplomacy entirely. But, judging from his words and actions at the United Nations and State Department, he sees diplomacy as a game for the powerless, not so much for the powerful.

Trump’s selection of Bolton follows hard on the heels of his nomination of CIA Director Mike Pompeo to become secretary of State, replacing the more moderate Rex Tillerson. Unlike Bolton’s job, Pompeo’s does require Senate confirmation, and that is not a given.

Pompeo, too, is a hard-liner on Iran and North Korea. So Trump appears to be increasingly surrounding himself in the Situation Room of the White House with people who possess two key qualifications: They believe firmly in the efficacy of U.S. military force; and they tend to agree with Trump on policy.

Bolton was an ardent supporter of the Iraq War as a State Department official in 2002. And he unapologetically defends it to this day.

Some worry that, by encircling himself with like-minded hawks, Trump may be recreating the key condition that led to the 2003 Iraq War: what George Orwell called “groupthink.”

For all his support for sending U.S. citizens off to wage wars overseas throughout the years, Bolton himself declined to fight in his generation’s conflict.

Bolton backed the Vietnam War, too, at least at first. But after he graduated from Yale in 1970, he joined the National Guard and went to law school.

“I confess I had no desire to die in a Southeast Asian rice paddy,” Bolton wrote in an article in his Yale class’s 25th reunion book, according to the Yale Daily News. “I considered the war in Vietnam already lost.”