Andres Manuel Lopez Obrador appeals to much of Mexico's middle class because he is often recognized as a modern leftist leader. Unfortunately, he's not. As Jorge Castaneda has recently written in Foreign Affairs, Obrador, and some of the rest of Latin America's new "leftists", really don't come from the left at all but are part "of the great tradition of Latin American populism...nationalist, strident, and close-minded."

What Lopez Obrador actually embodies is a new, dangerous reincarnation of the Institutional Revolutionary Party (PRI). While the old PRI was at least kept in check by its enormous political apparatus, Lopez Obrador's government would be reined in only by the limits of one man's grandiose, messianic vision of himself. That is dangerous news in a country so prone to idolizing and then -- upon the predictable failure of populist recipes -- rejecting, even destroying, its political leaders.

Lopez Obrador's most troubling trait is his mistrust of the world. Under him, Mexico would turn its back to the world; economically, diplomatically and even, I'm afraid, culturally. He has repeatedly stated that he does not believe in any sort of structural reform or foreign investment, even if Mexico badly needs both. Through his populist and class-oriented rhetoric, he has irritated social tensions in Mexico. His disregard for the rule of law and his genuine contempt for the judicial process are bad omens. What's worse: he has made promises that are either financially unsound or just plain impossible. He's a social spendthrift who could wreak havoc on Mexico's hard-fought macroeconomic balance.

Still, according to the last polls before this Sunday's election, Lopez Obrador appears set to win Mexico's presidency.

How would Obrador's victory affect Latin America? It's a tough call. As Moises Naim has pointed out before, Latin America is torn between Chavismo and Chilenismo: between a paranoid, anachronistic, irresponsible, even neurotic left and a modern, driven, centrist and fiscally sound one. Lopez Obrador is neither Chavez nor Lagos. He is not Morales either. As a matter of fact, it is difficult to guess where he will end up ideologically. By all accounts, Lopez Obrador will probably lack Chavez's anti-imperialist zeal (he can't afford it, not with Mexico's ties to the United States). Unfortunately, he will also lack Lagos's and Lula's penchant for intelligent reform.

It will not be until well into 2007 when Lopez Obrador's true colors will start to show. How will he handle the Unites States? "We will convince them that nothing will be solved with walls", he said in the second presidential debate (he has also said that he, with his messianic wand, will also "convince" addicts to stop using drugs). How will he deal with Chavez and Castro? Will he try to renegotiate the NAFTA? He has threatened to do so, even if it is all but impossible. In any case, when López Obrador finally shows his hand, Latin America as a whole will change politically.

If he turns out to be a hard-liner, Lopez Obrador will become a real headache for the United States, of course. But even if he surprises everyone and suddenly becomes a realist, his relationship with the United States will be strained at best. One of the mantras of PRI-inspired populism in Mexico is to be wary of "the country to the north". "The next president of Mexico will not be a puppet of the government of the United States", Lopez Obrador says, in true Chavista style, every time someone asks him about Mexico's distant neighbor.

How should the US government respond? With subtle and intelligent diplomacy (one can always hope). Just like the rest of the world, Mexico has become increasingly anti-American. The only way to defuse this and other preconceptions is to engage Mexico in a whole new way. But that will take an awful lot of imagination and, what's worse, a willingness to spend political capital, even when, as seen in the recent immigration debate, such disposition seems to be in short supply in Washington.

A Clarification: Earlier versions of this post were headlined "Lopez Obrador is Dangerous," a phrase from the post that editors felt more accurately summarized the piece than the headline recommended by Leon Krauze in the un-edited version of his commentary. As several readers have pointed out,"Lopez Obrador: a danger for Mexico" is the slogan of one of Lopez Obrador's opponents for the Mexican presidency. It was not the intention of the author or PostGlobal to indicate support for the other candidate. We have therefore changed the headline back to Krauze's original.