President Donald Trump loves to praise "tough guy" world leaders like Russian President Vladimir Putin and, more recently, Turkish President Recep Tayyip Erdoğan.

This sort of tough-guy foreign policy is fragile because egos can be bruised easily.

And when tough guys clash, normal people get hurt.

Emily Tamkin is a freelance writer who has written for Foreign Policy, BuzzFeed News, The Washington Post, and Politico.

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Last week, after Turkish President Recep Tayyip Erdoğan agreed to suspend attacks to "allow" Kurds to vacate the area in northern Syria from which the US had previously and unexpectedly withdrawn its military, US President Donald Trump heaped praise on Erdoğan.

"I just want to thank and congratulate President Erdoğan. He's a friend of mine, and I'm glad we didn't have a problem because, frankly, he's a hell of a leader, and he's a tough man," Trump said, adding that the Turkish president is a "strong man."

The chummy remarks came a week after the US president sent a letter to his Turkish counterpart warning him not to be "a tough guy." Even so, it appeared that, in looking to compliment Erdogan, Trump turned to what he considers to be the highest praise possible: tough.

This is far from the first time that Trump praised a leader for being tough. That the president seems to prefer strongmen to traditional allies is one of the constants of his otherwise chaotic foreign policy.

Trump is in office for it at the right time. While this is hardly an era of great men, it is a time ripe with tough guys pushing tough-guy foreign policy.

And when that tough-guy attitude leads to disastrous action, as it inevitably does, the results are catastrophic for those whom the policy really affects.

The cult of the tough guy

Tough-guy foreign policy is based on the idea that strength, above all, is what matters, and that the way to seem strong, in their minds, is to project an image of traditional masculinity.

The classic of the genre is Russian President Vladimir Putin, who rides horses and goes fishing shirtless (experiences captured on film and released by the Kremlin).

Putin is an avowed fan of judo and plays hockey. His country reportedly set up a national doping project so that its athletes might appear the toughest and strongest at the Olympics. He told Oliver Stone, in his questionable documentary on the Russian president, that only women have bad days and he would not shower near a gay man so as not to provoke him.

And this is the machismo that Putin demonstrates in his foreign policy too. The Russian president brought his dog out to shake German Chancellor Angela Merkel, who reportedly has a fear of dogs after being attacked in 1995, threatened to string then-Georgian President Mikheil Saakashvili up "by the balls," and reminded us all that he could take out capital cities in a matter of days.

But while Putin may be the original tough guy, he is far from the only one these days.

There is Trump, obviously. But there is also Filipino President Rodrigo Duterte with his drug war and fond recollections of having personally killed people. Hungarian Prime Minister Viktor Orban has positioned himself as the defender of Christian Europe, and Trump also praised Orban as a "tough man." There is North Korean dictator Kim Jong Un, of whom Trump said, "I was being really tough and so was he." And, of course, there is Erdogan.

To a point, tough-guy foreign policy has its merits. These elected and unelected men can find common ground in being tough guys and keep from killing one another's citizens, even if it is accompanied by embarrassing photo shoots, egregious human-rights abuses, and disparagement of women.

The limits of tough-guy policy

But tough-guy foreign policy works only to a point.

When the tough guys' interests inevitably come into conflict, and when the common ground crumbles beneath them, the machismo can become a liability.

Because toughness is not, in fact, a foreign policy, and personal chemistry between world leaders, even if it is predicated on something as powerful as traditional masculinity, is not necessarily enough to maintain a bilateral relationship.

If the thing these men have in common is that they resort to projection of strength, they will at some point project it to make one of the other tough guys seem weaker. After all, not all of them can be the toughest guy all the time.

The shaky nature of tough-guy foreign policy is why the talks between the US and North Korea could go off the rails so easily. It's why it's so disconcerting that the US withdrew from its landmark nuclear agreement with Russia roughly a year after Putin and Trump had their hours-long meeting in Helsinki. And it's why we wait to see what Erdoğan meant when he said he wouldn't forget Trump's letter — and that "it should be known that when the time comes, necessary action will be taken regarding this issue."

Tough-guy foreign policy is appealing to ego, but an ego can easily be bruised, and the consequences can be a nuclear arms race.

Whether the tough guys win or lose, the people who depend on real strength, and not a cartoonish version of it, suffer.

Turkish air strikes crashed down on the hours-old US-Turkish deal. Ankara had picked its military offensive back up. Fourteen civilians were killed by this hell of a leader, this tough man, this strong man.

Subsequently, Erdoğan reached another deal in Syria — this time with Vladimir Putin, who is, for now, the new guarantor of the Kurds. Later, Trump announced that with the Kurds gone Turkey had agreed to keep the ceasefire in place. "People are saying, 'Wow, what a great outcome — congratulations,'" the president said.

He announced this as a victory. For a tough guy, everything has to be.