In a recent column, I cut the Mexican government some slack over its publication of a cartoon-laden guide to crossing the border. Critics claimed the Mexican government was encouraging its citizens to break the law. I viewed it differently. But now the Mexican government has really stuck its nose in our business. And this time, critics of Mexico's technocrats have every reason to carp. Last week, the Mexican foreign minister got his country in the debate over our state's Proposition 200. Luis Ernesto Derbez said Mexico would like to see the controversial voter-approved law overturned. He said if our courts don't strike down Prop. 200, Mexico may lodge a complaint in an international tribunal. "We are … first using the legal capacities of the United States itself and … if that does not work, bringing it to international tribunals," The Associated Press quoted Derbez as saying in a radio interview. For someone supposedly astute on American civics, and on the ways U.S. citizens react, Mexico's chief diplomat is clueless. Mexico has no business chiming in about Prop. 200, which requires residents to prove American citizenship when registering to vote or applying for some state benefits. It also requires voters to show identification at the polling place. Proposition 200 is law. A court challenge has failed. The federal Justice Department sees nothing wrong with it. Still, the voter-approved law will not stem - or even dent - illegal immigration into Arizona. Undocumented immigrants do not come here to vote, and few manage to get on welfare rolls. Prop. 200 will hurt American citizens, not undocumented Mexican immigrants. The new law will make voter registration and voting far more difficult for ethnic minorities. On that ground, Mexico has no legs to stand on. Derbez was right when he remarked that the law could encourage racial discrimination. But he was wrong to publicly denounce a law his country can do nothing about. Before Mexico starts criticizing Prop. 200, no matter how onerous its effect will be on Arizona's minorities, it should look under the rug covering its own problems. Mexico has a long history of discrimination against its poor and indigenous people. It has no credibility in its cries of discrimination against ethnic minorities in Arizona and the United States. Instead of focusing on this side of the border, Mexican officials should show a little more concern about the women of Ciudad Juárez, who continue to disappear and turn up dead. In Ciudad Juárez, across the border from El Paso, more than 300 women and girls -perhaps as many as 400 - have been stabbed, strangled and bludgeoned to death since 1993. Many of them were sexually assaulted. The Mexican government puts the figure at less than 300 and in the past year stepped up its investigation. Still, the victims' families and women's rights groups have accused the Mexican government of ignoring their pleas and demands. Mexican and international critics have accused Mexican authorities of bungling the investigations and covering up the murders. Mexican courts have sentenced 12 men for the murders, but critics accuse authorities of doing too little, too late. And last month - at about the same time Derbez chided us for Prop. 200 - a United Nations arm slapped Mexico hard, accusing it of "grave and systematic" rights violations because the victims are largely poor or working-class women. Thanks, Mexico, for your concern over Prop. 200. But we don't need it. The women of Juárez need it more.