President Trump’s sudden cave-in to China on Thursday reveals that, despite his reputation as a master of the deal, he knows little about bargaining with major foreign powers.

Soon after he won the election, but before he took office, Trump said that he might scuttle America’s longstanding acceptance of the “One China” policy—the recognition of the People’s Republic of China, with its capital in Beijing, as the only state to be called China. (Taiwan, which calls itself the Republic of China, could still receive defensive weapons but not otherwise be treated as an independent state.)

That was Trump’s first mistake. Any expert in the region could have told him that the Beijing government views “One China” as an existential matter, not open to discussion. When told this after the fact, Trump said—publicly—that he would use his threat as a “bargaining chip” to get better terms on trade or other issues.

This was Trump’s second mistake. If his best-seller The Art of the Deal doesn’t include a chapter titled “If You Want to Use Something as a Bargaining Chip, Don’t Say It’s a Bargaining Chip,” it’s a pretty worthless book. If the Chinese had been worried before that Trump might carry out his threat, they no longer had cause for concern. He’d pretty much winked and nudged that he was bluffing. They could stand their ground with no risk.

And so, this week, when Trump was wrapping up his phone calls with foreign leaders, Chinese President Xi Jinping announced that he would not even speak with Trump until he explicitly reaffirmed the One China policy. In response, on Thursday, Trump reaffirmed it.

It’s good that, on this point, Trump reconciled with reality. But it’s bad that, after so avidly embracing an alternative reality and making it part of a tough stance toward China generally, he dropped it so swiftly, in exchange for nothing but a presidential phone call.

Our Asia-Pacific allies were already nervous about several of Trump’s remarks, which raised doubts about his commitment to their security. Their fears were so serious—and so justified—that Secretary of Defense James Mattis flew to the region and reassured them face to face. Now Trump’s 180 on China must make them leerier still of any promises he makes or beliefs he claims to hold. It’s likely that some of these allies will soon seek separate deals with China, another large power, or among themselves: some sort of arrangement that doesn’t depend on—or, as it will turn out, benefit—the United States.

Trump campaigned on the premise that, because he’d made great deals for his real estate empire, he could also make great deals for his country. Previous presidents made “terrible” deals, he scoffed, because they didn’t understand the game; he would make great deals because he practically invented the game. A deal is a deal is a deal—that was his assumption, regardless of whether the deal is made with New York City’s Department of Buildings, some vendor on a construction project, or the People’s Republic of China. What he didn’t understand was that the game of international relations is very different: In global power politics, no outside arbiter can settle disputes, and you can’t avoid a loss by declaring bankruptcy.

Meanwhile, on Friday, as was already scheduled, Trump welcomed Japanese Prime Minister Shinzo Abe to the White House, then flew with him to Florida for a weekend of golf and talks. Abe played their joint press conference shrewdly: congratulating Trump for his election victory, complimenting Trump’s golf game (and deprecating his own), and touting the many jobs created by Japanese car factories in American territory. Abe has learned what many foreign leaders have learned—that the way to deal with Trump is to act like a grateful, admiring friend. Trump wears his buttons—his need for devotion and respect—so visibly on his sleeve that almost anyone can gain favor, at least for a while, by simply pushing them ever so gently. Vladimir Putin has done this; so has Theresa May (on Barack Obama’s advice); so, in a recent phone call, did Czech President Milos Zeman—lavishing praise, telling jokes, and talking about golf so amiably that Trump pronounced him “my type of guy” and invited him to the White House. Many more leaders can be expected to emulate these tactics.

But good personal relations alone aren’t the basis of sound foreign policy. Good relations grow out of common interests, not the other way around. Words and actions have consequences, and these consequences can intensify when a leader’s ultimate interests and intentions are as nebulous as Trump’s are. Politico reported this week that Trump is surprised that the presidency is so much harder than he thought it would be—and so much different from running a business. Yet it’s been only three weeks. He’s had to face no crises, other than those of his own making; he’s made only one life-or-death decision—involving the raid on Yemen—and he seems incapable of facing the possibility that it might have been a failure. Everyone who thinks seriously about these matters is nerve-racked wondering what he will do if he’s tested by a genuine threat. And it’s all the more worrisome to note that, at some point, every president is.