While the U.S. Congress dithers over how best to stop illegal immigration, the Mexican people may have already decided the issue this past weekend. Mexicans went to the polls Sunday to pick a new president, only the second presidential election in the last 75 years that could be characterized as a truly free and democratic contest. The more conservative, free-trade-oriented candidate, Felipe Calderon of the National Action Party (PAN), appears to have eked out a slim victory with a few hundred thousand more votes than the leftist Andres Manuel Lopez Obrador. Although Lopez Obrador, the former mayor of Mexico City...