Donald Trump went to Mexico Wednesday on a risky, last-minute trip in advance of his big policy speech on immigration. He had two goals: to provide a dramatic, newsy preview of his immigration policy speech on Wednesday night, and to look presidential.

It worked.

After meeting Mexican president Enrique Peña Nieto, a sober and subdued Trump stood at a podium opposite his counterpart, listened patiently as Peña Nieto described their meeting, and then briefly offered his own impressions. Trump listed his 5 policy priorities with respect to Mexico, took a couple of questions and ended the 33-minute press event.

Both men laid out their positions and acknowledged some areas of conflict. But there were no fireworks at the press conference, and Trump ended his remarks by calling Peña Nieto a "friend."

The visit comes after more than a year of tough, sometimes racist comments from Trump on Mexicans and Mexican-Americans. Trump rode his hardline positions on illegal immigration—build a wall, make Mexico pay for it, no legalization, forced mass deportation—to the Republican nomination. Some GOP primary voters agreed with his views, others admired his willingness to make his case forcefully and without regard to warnings from the consultant class and others about the dangers of doing so.

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.

As the race enters its final nine weeks, there is one question: Can Donald Trump behave like someone other than Donald Trump for long enough to convince the American people to elect him president against a hopelessly corrupt politician who is as widely disliked as he is?