The decision of Congress to build a wall dividing Mexico and the United States can only be considered as completely nonsensical. It is the triumph of prejudice over reason. It is a total waste of money. It is blaming innocent immigrants for the terrorist attacks on America. It is the exploitation of fear of terrorism for political ends. It's also a product of the Mexican government's stultifying, inefficient foreign policy. The wall is clearly useless _ and a killer.

      The construction of this wall surely is the worst idea of 2005 to emerge from Congress. It's hard to imagine how $8 billion dollars could be so blithely thrown away. You don't have to be a nuclear physicist or a brain surgeon, or even someone of average intelligence, to understand that if you build a 692-mile wall on a 1,948-mile border, there is still a 1,256-mile gap for anyone who wants to cross into the United States without a visa.

      It is incredible, however, that 260 congressmen _ who are supposed to be some of the best informed people in the world _ voted in favor of an amendment to build such a wall. Why would they do something like that? First, because they don't want to lose their seats: Even though they know that wall won't stop illegal immigration, few congressmen dare to be seen as weak in the war against terror. That's populism at its worst: they say and do what people want to hear, not what actually works. And second, they voted for the wall because they seem to believe more in today's anti-immigrant propaganda than in unequivocal data.

      Even if it is obvious, it has to be pointed out yet again: not one of the 19 hijackers that killed almost 3,000 Americans on Sept. 11, 2001, entered the United States through the border with Mexico. Besides, a wall will not prevent another terrorist attack. It will only give a false illusion of security.

      We need to be pursuing Osama, not Pedro.

      Every minute, on average, one immigrant slips illegally into the United States. And this can't and will not be stopped by a wall. Hunger is mightier than any wall. A Latin American can earn in the United States 10 or 20 times more than in his native country. That is why they come. And they should be welcomed, not rejected.

      Most of the half million illegal immigrants who annually enter the country _ according to estimates by the Pew Hispanic Center _ are not criminals or terrorists. These immigrants make America a better country: They take work Americans don't want, they pay taxes, create jobs, control inflation, contribute to the retirement benefits of the elderly and are the backbone of many industries (among them agriculture, hotels and construction, to mention only three). Even the same 260 congressmen who voted for the wall profit from their work directly or indirectly.

      Walls kill, as the old Communist Berlin wall showed us, or the wall around the North African Spanish enclave, Melilla, does. The same holds true of the wall on the Mexican-American border. Last year, according to the U.S. Border Patrol, 464 immigrants died trying to cross illegally into the United States. A new wall, built in parts of Texas, New Mexico, Arizona and California, would cause many more fatalities by forcing immigrants to take ever more dangerous routes through deserts and mountains.

      Blame for the wall, it has to be said, lies not only in populist, ill-informed U.S. congressmen or in their exploitation of American voters' fear. It also sits with the Mexican government.

      Mexico's foreign policy, focusing on a negotiated immigration agreement with the United States, has been a shocking failure. It has achieved nothing. On the contrary, it has allowed the advancement in Washington of the most abominable idea in the history of the two allied countries' relationship: the construction of a dividing wall.

      President Vicente Fox's government has no visible head who explains Mexico's position, in English, every day and constantly, to journalists and politicians in the United States. I don't see Mexican Ambassador to Washington Carlos de Icaza or Foreign Minister Luis Ernesto Derbez on CNN, FoxNews, ABC, CBS or NBC. I do not mean to criticize. Perhaps their efforts are being done quietly behind the scenes. But this is no for quiet, it is time for shouting. Mexico's languid foreign policy suffers from a huge vacuum in leadership and visibility.

      Former Mexican President Carlos Salinas de Gortari may be whatever you care to call him _ there's plenty of room to throw darts _ but his administration did know how to conduct public relations campaigns abroad. During the approval of the North American Free Trade Agreement (NAFTA) in the American Congress in 1993, the Mexican government hired some of the most powerful lobby groups and public relations agencies in the United States. The Salinas government identified the most influential journalists and politicians, and every time a comment was made against NAFTA, there was a phone call or reaction _ immediately. His operators besieged the media, in English and Spanish, for months.

      Fox hasn't done anything like that and the results are there: NAFTA was achieved, an immigration agreement was not.

      What good is it to have a special war room at the Mexican Foreign Ministry to examine what American congressmen are saying about the immigration issue if afterward Mexico's officials don't follow them up with visits, phone calls, official statements and personal pressure? Has any Mexican government representative ever visited any of the 260 American congressmen who voted yes on the wall?

      Politics is not a game of good intentions. In politics, things have to be asked for, pushed and demanded. And if the Mexican government realized it couldn't negotiate an immigration agreement with President George W. Bush, at least it should have made sure the wall wasn't a viable idea. They failed to do even that.

      The proposed "Border Protection, Anti-Terror and Illegal Immigration Control Act," already passed by the House of Representatives, which will be examined by the Senate early next year, cannot solve the immigration problem with a wall. It only delays and complicates it. It also doesn't confront the real white elephant: what are they planning to do, beyond criminalizing their presence, about the 11 million illegal residents already here in the United States? It is impossible and impractical to deport them all.

      The great irony is that if the wall finally goes up, it undoubtedly will be built with the labor of illegal workers. Who else in the America is willing to toil for little more than $5 an hour to build dumb little walls in the sweltering desert?