Editor's Note: This article is one of 50 in a series about Trump's first two years as president.

On May 16, 2017, about a dozen members of the security detail of Turkey’s president, Recep Tayyip Erdoğan, attacked a group of mostly American protesters outside the Turkish ambassador’s residence in Washington, D.C. The bodyguards overran local police officers, punched and choked demonstrators, then kicked them repeatedly as they lay on the ground. Nine people were hospitalized for concussions, lacerations, and other injuries.

The attack occurred shortly after Erdoğan’s first official meeting with President Donald Trump, at the White House. Erdoğan had just arrived at the residence after that meeting. He was captured on video speaking to the head of his security team, who appeared to give an order to a nearby bodyguard; the bodyguard nodded and walked over to a cluster of security personnel, who then rushed the protesters. (They’d been demonstrating against the Turkish leader, about 100 yards away.) Erdoğan watched the attack impassively.

The reaction in Washington was furious. The House of Representatives voted 397–0 in favor of a resolution to bring the perpetrators to justice. Senator John McCain called for the expulsion of the Turkish ambassador. Federal prosecutors eventually indicted 15 of Erdoğan’s bodyguards, though all were back in Turkey by then.

Less troubled by the incident was Trump, who was silent in the aftermath of the attack and has subsequently demurred when reporters have asked him about it. He offered no public comfort to the victims of the attack, no rebuke to the perpetrators, no statement of support for the bedrock rights of free assembly and free expression. Sean Spicer, then the White House press secretary, referred reporters to a State Department communiqué condemning the attack, and declined to comment further.

A month before the assault, Trump had reportedly been the first Western leader to congratulate Erdoğan on winning a referendum—a result disputed by election observers—that had greatly expanded the strongman’s powers, ratifying authoritarian rule. (A State Department spokesperson was more cautious, calling on Turkey to “protect the fundamental rights and freedoms of all of its citizens.”) Four months later, in September, Trump would meet Erdoğan again, in New York, calling him a friend and giving him “very high marks” for his leadership.

Trump has made it clear that human rights won’t play a role in his foreign policy; he’d rather make deals. The Justice Department dropped charges, without comment, against four of the bodyguards in November 2017, and against seven more in February 2018, the day before then-Secretary of State Rex Tillerson was to meet with Erdoğan in Turkey on a diplomatic mission. The Turkish president paid no price for the incident, which he blamed on the protesters and the police—indeed, he used it as domestic propaganda, a show of strength.

It bears mentioning, of course, that Turkey is an ally of the U.S., or at least a frenemy, and the diplomatic relationship between the two states must be handled with care. It may also bear mentioning that Trump’s name is affixed to two towers and an associated mall in Istanbul—Erdoğan presided over the mall’s 2012 opening ceremony—for which Trump collects a fee.

We learn the restraining influence that an American president has on foreign dictators only in the absence of that restraint. The Turkish incident was itself a small matter when compared with many other acts by authoritarians during Trump’s term—the killing of the Saudi journalist Jamal Khashoggi, the detention of the head of Interpol in China, a rash of unconcealed assassinations of dissidents worldwide. Erdoğan’s security detail has a history of thuggish behavior that predates Trump, but the incident was rich with symbolism, nonetheless.

What did Erdoğan see in the meeting with Trump that preceded the attack? Perhaps what so many others have seen: weakness beneath the bluster; a man unserious about his office, empty of patriotic spirit, unburdened by obligation to anyone but himself. Or perhaps something more like kinship: the moral disposition of a fellow traveler. We don't really know, of course, as irresistible as such armchair speculation can be.

What we do know is that soon after meeting with the American president—the leader of the free world, as that officeholder has sometimes been known—Erdoğan spoke to his head of security, then calmly looked on as his bodyguards attacked a peaceful and lawful assemblage of American citizens, on American soil.

And Trump did nothing.

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