Updated on August 31 at 7:07 p.m.

On an ordinary day, Donald Trump can’t stop talking about the wall.

His promise to build a huge wall on the U.S. border with Mexico at Mexico’s expense has been among the most consistent refrains through his presidential campaign. (He has spent the last two weeks backing away from another, his vow to deport undocumented immigrants.) His plan to compel Mexico to pay is one of the most detailed items on the otherwise sparse policy section of his website. He can’t help but bring it up at every campaign event, as he explained to The New York Times: “If it gets a little boring ... I just say, ‘We will build the wall!’ and they go nuts.”

But this was no ordinary day, and when Trump met Mexican President Enrique Peña Nieto Wednesday afternoon, the Republican presidential nominee didn’t even bring it up.

“Who pays for the wall? We didn’t discuss it,” he said during a brief press conference after the meeting.

When Trump made that comment, Peña Nieto was standing just to his right and said nothing. Two hours later, however, the Mexican president said in a statement that he had told Trump during their meeting that Mexico would not pay for the wall. Because no press was present in the room, it’s impossible to know who is telling the truth and who is lying. Throughout his campaign and career, Trump has shown a willingness to embellish, equivocate, and sometimes simply tell untruths. But Peña Nieto, under pressure from a Mexican public furious at the visit, said nothing in the moment and has an incentive to show his own citizens he stood up to Trump.

Trump’s decision not to bring up paying for the wall during what he described as a lengthy and candid discussion is surprising, and it leaves one of the most important questions about his visit to Mexico unanswered. The trip, hastily arranged and announced only Tuesday night, comes on the eve of what’s being billed as a major speech on immigration. But in his second journey abroad as a presidential candidate, and his first meeting with foreign leaders, Trump avoided the most controversial issue. He did assert the U.S. right to construct a wall—a far cry from the promise that Mexico would fund the construction.

Trump arrived in Mexico City earlier Wednesday afternoon, and met with the Mexican president, who is often referred to as EPN, at Los Pinos, the Mexican executive mansion. As they met, conflicting reports suggested they might or might not hold a press conference, but eventually the two men emerged and stepped to a pair of lecterns. A Mexican flag stood behind Peña Nieto; there was no flag behind Trump.

EPN went first, speaking in Spanish. For a leader who had previously likened Trump to Hitler and Mussolini, Peña Nieto was restrained. But his statement was a firm, methodical rebuttal to Trump’s campaign rhetoric, even as he offered a few openings for collaboration with the U.S. He emphasized that he would be ready to work with either a President Trump or a President Hillary Clinton.

“Our countries are very important to each other,” he said. “Mexico is very important for the United States, just as the United States is very important for Mexico.” He said the two nations innovate together and noted close collaboration on security.

Peña Nieto then embarked on a live fact-check on Trump’s platform. First up: NAFTA, the 1994 treaty that Trump has pledged to either renegotiate or tear up.

“I expressed my conviction that NAFTA has done a lot of good for the United States and Mexico,” EPN said, noting major U.S. experts to Mexico and studies that find up to 6 million American jobs rely on trade with Mexico. Rejecting Trump’s manichean approach to trade, he said, “I don’t think that commerce can be considered a zero-sum game. It must be seen as an effort that generates value to both parties and makes North America the most competitive and innovative region in the world.”

But Peña Nieto acknowledged that NAFTA was now more than two decades old, and he said he would be willing to discuss updating the treaty, as long as any changes were mutually beneficial.

Next up: Immigration. While acknowledging American anger about illegal immigration, EPN noted that it peaked 10 years ago and is now net negative. He also complained about the flow of cash and guns into Mexico from the United States, and noted that many of the people crossing the U.S.-Mexico border without documents are not Mexicans.

Peña Nieto acknowledged that every country has a right to secure its borders, but added, “I also think that a real collaboration between friends and allies is the best way to attain this.” As he did in a tweet last night, he spoke of his duty to protect Mexicans “wherever they may be,” and he asserted the need to respect Mexican citizens, presumably a reference to Trump’s statements last year that Mexican immigrants are “bringing crime. They're rapists.”

But Peña Nieto failed to extract any apology from Trump for his various attacks, nor did he chastise the American. This may stir more backlash for a Mexican populace already disaffected with its president and upset about his invitation to Trump.

Then it was Trump’s turn. He spoke carefully, reading a prepared statement. He said it was an honor to meet with the president, and he added, “I happen to have a tremendous feeling for Mexican Americans, not only in terms of friendships but in terms of the tremendous numbers that I employ in the United States, and they are are amazing people.”

“The United States must take action to stem this tremendous outflow of jobs from our country. It’s happening very day. It’s getting worse and worse and worse.”

He pushed back on EPN’s view of NAFTA, saying he had shared his view that Mexico had benefited far more than the U.S. and insisting on “fair and reciprocal trade.”

“I expressed that the United States... must take action to stem this tremendous outflow of jobs from our country. It’s happening very day. It’s getting worse and worse and worse,” Trump said. (In fact, recent trends show insourcing of manufacturing jobs to the United States after years of losses.)

Trump outlined five steps he said the U.S. and Mexico could collaborate on: Ending illegal immigration; the right to build a physical wall on the border; dismantling drug cartels; updating NAFTA; and keeping manufacturing wealth in the hemisphere.

Trump more than once mentioned the importance of keeping economic gains in the Western Hemisphere. It’s a new motif for the Republican, if a somewhat uneasy one: The idea of hemispherical collaboration undergirds NAFTA, the very treaty he has so harshly denigrated. The America First candidate was extolling the benefits of an Americas First policy. He closed by calling Peña Nieto—the president of a country Trump called an “enemy”—a friend.

Trump’s visit to Mexico was a major risk, and despite 11th-hour planning, it went off without major hitches. The press conference didn’t end with an acrimonious Love Actually moment. In meeting with a foreign leader, Trump perhaps achieved a measure of looking presidential, something his aides told CNN was a major motivation behind the brief trip. Trump might be graded on a curve on this issue; his trip was far shorter than the one Mitt Romney took in 2012 or the one Barack Obama made in 2008, offering far less depth but also fewer settings for disaster. He avoided that.

But the he-said-he-said on paying for the wall casts a shadow over the whole visit. Assuming it is Trump and not EPN who is telling the truth about the wall, Trump wasn’t willing to gamble by putting the negotiating skills he frequently boasts about to test by asking the question he’s usually so eager to spring: “Who’s gonna pay for the wall?” The risk that Peña Nieto might contradict him publicly was simply too great.