The Pentagon opted for continuity Thursday in naming Marine Gen. James Mattis to take the reins of Central Command, the general who oversees US military operations and planning in crucial countries including Afghanistan, Iraq, Iran, and Pakistan.

If confirmed by the Senate, Mattis would replace Army Gen. David Petraeus, who stepped down from his post at Central Command to take direct control of the US war effort in Afghanistan after the resignation of Gen. Stanley McChrystal.

Mattis and Petraeus are the joint architects of how America now fights counterinsurgencies. Drawing extensively on their experiences as commanders during the earliest and most tumultuous period of the Iraq insurgency, Petraeus and Mattis wrote the military's primary manual on counterinsurgency.

They are, in many ways, the twin pillars of modern American warfare – erudite, inventive, and allied in a conviction that defeating an insurgency requires a fundamental revision of how soldiers and marines fight.

Yet unlike Petraeus, whose personality and bearing exude the soldier-scholar, Mattis comes with a mouth – and a mentality – often not far removed from the mess hall.

Speaking of the Taliban, he said in 2005: "It's fun to shoot some people. I'll be right upfront with you. I like brawling." To Iraqi military leaders in 2003, he said: ""I come in peace. I didn't bring artillery. But I'm pleading with you, with tears in my eyes: If you [expletive] with me, I'll kill you all."

Following the professional demise of McChrystal, who resigned after belittling numerous members of the Obama administration in a Rolling Stone article, Mattis might seem an odd choice.

But Defense Secretary Robert Gates said Thursday that Mattis has learned his lesson. And perhaps more important, Mattis's comments were not aimed at the civilian chain of command, but rather spoke to his warrior's worldview.

Dubbed the "warrior monk," Mattis is single, is a student of history, and is a Marine to his core. Taken out of context, his comments might seem to be precisely the opposite of America's more nuanced counterinsurgency goals – protect civilians, use force with discretion.

But Mattis left behind a motto with the marines he led in Iraq's Anbar Province: "First, do no harm."

He is, in many ways, the model of what he wants his soldiers and marines to become: fierce when provoked and unblinking in the face of war's savagery, but determined to make intelligence and forbearance as great a measure of valor as violence.

In Iraq, according to a report in Slate.com, Mattis talked to his troops about fellow marines who cleared the road for an Iraqi funeral procession and even removed their helmets as a sign of respect – willingly making themselves vulnerable. To Mattis, who studied counterinsurgencies from Algeria to Lawrence of Arabia before deploying to Iraq, warfare is about risk, and the risks inherent in counterinsurgencies are as much about not fighting in order to win over the local population as fighting to kill enemies.

To underscore this, Mattis would even sometimes go on missions with his troops, sharing the risks that he was asking them to take.

In his new post as head of Central Command, Mattis would be called upon to exercise the more diplomatic sides of his character, routinely meeting with military leaders from Pakistan and countries in the Middle East.

Related: