Trump’s tendency to take up the position of the last person with whom he spoke on a given issue has been widely noted. Xi’s claim that North Korea is an intractable problem is a widely held one, and North Korea bedeviled Presidents Obama, Bush, and Clinton, too, but it’s disconcerting that a foreign leader could so quickly dazzle Trump. The combination of little knowledge and practically no ideological commitments also makes the ongoing battle between factions in Trump’s White House much higher stakes than they might otherwise be.

Trump’s about-face on China and North Korea is just one of several headspinning reversals over the last week. As I wrote today, many of those changes in position seem to reflect a simple transition: Before, Trump didn’t know the facts of what he was talking about; now he does. He insisted time and again, over the course of nearly two years, that China was nefariously devaluing its currency, but now he realizes that since 2014 Beijing has actually been spending heavily to prop it up. He used to think the U.S. should avoid engagement in Syria; now that he’s seen evidence of chemical-weapons use and barrel bombs, both of which Bashar al-Assad was already using when Trump was against intervention, he has changed his mind. He used to think Russia could help solve the Syrian problem; now he understands that Vladimir Putin is one of Assad’s two most important patrons.

These reversals are notable because, despite common skepticism of campaign promises, politicians usually try to do most of what they said once they enter office. Even in a mass-media era where the winner of most presidential elections is the candidate with the most winning personality, presidents continue to view their mandate as based in their policy priorities—partly because it might be discouraging to think otherwise, and partly because their core supporters demand it.

Take Barack Obama, who expended massive political capital early in his term on passing a huge overhaul of the health-insurance system. As a matter of policy and justice, this may have been wise, but as a matter of politics, it stank: Even as public opinion turned sharply against reform, the White House kept its foot on the gas. The blowback helped doom Democratic control of the House of Representatives, and the resulting law was consistently unpopular—until, that is, Trump tried to repeal it.

Vast learning is neither sufficient nor necessary to be a successful president. Some of the commanders-in-chief with the most impressive academic resumes turned out to be mediocre or even bad presidents. Besides, all presidents face some sort of learning curve. Bill Clinton’s plans to allow gays to serve openly in the military quickly crashed on the shoals of political reality. George W. Bush’s denunciations of “nationbuilding” as candidate gave way to two huge nationbuilding efforts after September 11. Obama signed an executive order ordering the closing of the prison at Guantanamo Bay on his first day but never actually followed through. Nonetheless, the scope of Trump’s recent reversals, and his frank admission of not knowing the facts, sticks out.