But the significance of his visit to Mexico has less to do with immigration policy itself and more to do with broader perceptions of Trump as a man and as a potential president. Hillary Clinton began the general election portraying Trump as just another Republican who was likely to do nasty Republican things if he were elected president. She changed her approach at the Democratic convention, arguing instead that Trump was irrational and dangerous, unfit to serve as commander in chief. That effort culminated in her speech last week attempting to make Trump own the “alt-right” and its craziness. Trump, she argued, was unlike mainstream Republicans like Paul Ryan and Ted Cruz. He was a threat to the republic, an ignorant loudmouth who couldn’t unite the country at home and who would bungle the kinds of delicate diplomacy that she’d undertaken as secretary of state.

On Wednesday, Trump made those concerns look overblown. He stood across from the president of a country whose citizens he has often cast as villains and calmly walked through policy differences in reasonable and rational manner. His angry rants about Mexicans as rapists and criminals, about Mexican-Americans’ views shaped by their heritage, were nowhere to be heard. Trump’s sharp edges were rounded, his hot rhetoric cooler. If voters are concerned that Trump is incapable of behaving like a statesman—and many of them are—Trump showed them that at least on this day, he could. He was, ever briefly, the kind of Trump many Republican elected officials have long hoped publicly that he could become.

Can it last? There are reasons to be skeptical. He’s had good moments in the past. The Trump on display in Mexico is not the real Trump.