In The Art of the Deal, President Trump presents his deal making — by which he means his avarice and swindling — as an artistic enterprise. "Deals are my art form," he writes in his best-selling book that he didn't write. "Other people paint beautifully on canvas or write wonderful poetry. I like making deals, preferably big deals."

Trump's forte is con artistry. He sells books he doesn't write to people who don't read. He failed as a businessman but succeeded as a fake businessman on TV. The supreme irony of his life is that he poses as a dealmaker when he is the opposite. Trump doesn't make deals. He breaks them.

Trump's perfidy has global consequences. His decision this week to withdraw troops from northern Syria, reportedly made after a phone call with Turkish President Tayyip Erdoğan, surprised and infuriated lawmakers, including Republicans. Rep. Liz Cheney (R-Wyo.) called it "a catastrophic mistake," Sen. Marco Rubio (R-Fla.) called it "a grave mistake that will have implications far beyond Syria," and Sen. Mitt Romney (R-Utah) called it "a betrayal." Trump's abandonment of the Kurds, Sen. Lindsey Graham (R-S.C.) said, sends "the most dangerous signal possible — America is an unreliable ally." America is an unreliable ally because its president is an unreliable person.

If there's a constant in Trump's life, it's betrayal. He has betrayed his business partners, his customers, his employees, his friends, his wives, and his voters. A man who is willing to betray those closest to him will not hesitate to turn his back on foreigners thousands of miles away.

In addition to abandoning the Kurds, the Trump administration is withdrawing from the Open Skies Treaty. Its most glaring defect is that it's a treaty. Trump opposes treaties because he loathes any agreement that redounds to other people's benefit. Moreover, treaties, like all reciprocal transactions, impose obligations on the signatories. To Trump, doing stuff for other people is for wimps and losers.

Since becoming president, Trump has extricated the United States from a host of international agreements. He pulled out of the Trans-Pacific Partnership ("a terrible deal"), the Paris Agreement ("a deal that punishes the United States"), the Iran nuclear deal ("the worst deal ever"), and the Intermediate-Range Nuclear Forces Treaty. He did so despite not knowing what any of them were. He also threatened to leave the World Trade Organization ("a disaster for the United States"; "they have been screwing us for years"), questioned the utility and fairness of NATO ("very unfair to the United States!"), and renegotiated NAFTA ("one of the worst trade deals ever") and the U.S.-South Korea Trade Agreement ("a horrible deal made by Hillary").

Thanks to Trump, the world no longer trusts the United States to honor its commitments. According to a Pew survey conducted last year, 82 percent of Europeans had no confidence in Trump's handling of international issues. Seventy-five percent of Canadians and 91 percent of Mexicans don't trust the president to do the right thing regarding world affairs. His numbers are bad even in Russia.

After Trump promised to send "an armada, very powerful" to deter North Korea in 2017, South Korean presidential candidate Hong Joon-pyo said, "If that was a lie, then during Trump's term, South Korea will not trust whatever Trump says." It was a lie. The U.S. Navy posted a photograph six days later of the fleet heading in the opposite direction.

Lesson: So long as Trump is president, the United States cannot be trusted.

Trump's foreign policy mirrors his personal behavior. It is erratic, unreliable, duplicitous, greedy, shortsighted, self-destructive, easily manipulated, unprincipled, and callous. The key to understanding it is understanding him. Lacking a coherent worldview, Trump mines his own insecurities for material and projects them onto the United States, which he casts as a perennial victim of other countries' cunning and conniving. "The U.S. is always the 'sucker,'" tweeted the man who fell in love with Kim Jong Un.

When Trump talks about America, he's really talking about himself. The world is laughing at us (me). America (me) first! "Nobody ever wants to work with the United States," he said. Just as nobody ever wants to work with Trump, and for good reason: Just as he breaks laws and betrays his friends, America under his stewardship neglects its responsibilities and deserts its allies.

Last week, Trump blamed his phone conversation with Ukrainian President Volodymyr Zelenskiy on Energy Secretary Rick Perry, who dutifully accepted responsibility.

Trump demands loyalty from those he inevitably betrays. "We could use some more loyalty," Trump said in 2017. Eight hours later, he berated Attorney General Jeff Sessions as "VERY weak" for behaving ethically. Betraying people while demanding their loyalty is like divorcing your wife because you cheated on her.

Note to Republicans: Trump will do to you what he did to the Kurds.

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