Trump is not a head of state, so his last-minute trip to Mexico on Wednesday is not technically a state visit. But it’s not a vacation either, unless he and Mexican President Enrique Peña Nieto are going to split a pitcher of virgin margs at Señor Frog’s. Instead, his trip is going to be something state visits rarely are: unpredictable.

Here’s The Washington Post about how state visits usually go down:

Overseas visits by senior U.S. officials normally require weeks of intricate planning on both sides, as every movement and meeting is plotted. When more security is required, such trips become even more complicated.

Trump, on the other hand, gave Mexico less than 24 hours notice. Of course, it’s very possible that Trump is going to be very, very boring in Mexico. His voters are loyal and probably won’t be put off by him shaking hands and playing nice with Peña Nieto. Meanwhile, playing statesman could help win over Republican fence-sitters.

That is, at least, what would happen if someone other than Donald Trump visited the president of Mexico. But we’re talking about Donald Trump at a moment when Donald Trump needs to make a splash. One simple fact explains why Peña Nieto and Trump are meeting: They’re both extremely unpopular (though Peña Nieto can’t touch Trump) in their home countries and and both have incentives to stand up to one another.

Which means that the Trump-Peña Nieto meeting is being set up like a zero-sum game. Trump is going to tell Peña Nieto that Mexico has to pay for the wall; Peña Nieto is going to tell Trump to go fuck himself, ingratiating himself to both Mexican voters and future U.S. President Hillary Clinton. Both Trump and Peña Nieto have good political reasons to start a protracted feud with each other. And if they do? Best state visit ever.