For once, Republicans have forcefully spoken out against Mr. Trump. Graham said our Kurdish allies had been “shamelessly abandoned by the Trump administration.” Representative Liz Cheney of Wyoming, the third-ranking Republican in the House, said Trump’s decision is having “sickening and predictable” consequences. Representative Adam Kinzinger, an Air Force veteran, said on Face the Nation that “leaving an ally behind … is disheartening, depressing.” He added, “The Kurds found out on Twitter, for goodness’ sake. We have left them to the wolves. And the message this is sending to our allies around the world, I think, is really going to be bad.” Senator Mitt Romney, the Republican lawmaker who has been the most willing to speak the truth about Trump, declared on Twitter, “The President’s decision to abandon our Kurd allies in the face of an assault by Turkey is a betrayal.”

Indeed it is. But betrayal is hardly new to Trump, who routinely abandons people who trust in him or the nation he leads. By now, this behavior should come as a surprise to exactly no one.

Betrayal is a leitmotif for this president’s entire life. Think of how he cheated on his wives. Think of the infant child of a nephew who had crucial medical benefits withdrawn by Trump because of Trump’s retaliation against his nephew over an inheritance dispute. Think of those who enrolled at Trump University and were defrauded. Think about the contractors whom Trump has stiffed. Think of Jeff Sessions, the first prominent Republican to endorse Trump, whom Trump viciously turned against because Sessions had properly recused himself from overseeing the investigation into whether Russia had intervened in the 2016 election. Think about those who served in Trump’s administration—Rex Tillerson, John Bolton, Don McGahn, Reince Priebus, Gary Cohn, James Mattis, and many more—who were unceremoniously dumped and, in some cases, mocked on their way out the door.

Also think of how Trump has disparaged his own country while making excuses for strongmen. When MSNBC’s Joe Scarborough said Vladimir Putin “kills journalists, political opponents, and invades countries,” Trump replied that “at least he’s a leader.” Besides, Trump asserted, “I think our country does plenty of killing also.” And when asked whether Erdoğan was exploiting the coup attempt to purge his political enemies, Trump did not call for the Turkish leader to observe the rule of law, or Western standards of justice. “When the world sees how bad the United States is and we start talking about civil liberties, I don’t think we are a very good messenger,” he said.

As McKay Coppins put it in The Atlantic shortly after the president was sworn in, “Trump built his success on his willingness to toss aside mentors, friends, and family members during moments of frustration and chaos.” Serial betrayal is a central trait of Trump’s character, and his critics warned from the start against elevating such a person to the nation’s highest position of public trust. When the consequences are the serial humiliation of Cabinet secretaries and White House aides, they are easier for Trump’s political supporters to rationalize or overlook. But as the professor Robert King once declared, “Betrayal is a garment without seams.” The danger is far plainer when the victims of Trump’s betrayal are longtime American allies facing deadly force.