The Second Annual "National March for Immigrant Rights" , on the U.S.-Mexico border, began on February 2. Last year, the march was also held on February 2. What’s going on here? Why February 2? Answer: February 2nd is the anniversary of the signing of the Treaty of Guadalupe Hidalgo. That 1848 treaty officially ended the Mexican War and legally turned over most of the Southwest to the United States.The average American doesn’t know much about the Mexican War and thinks about it less. But here in Mexico they do think about it—a lot. In Mexico, everybody knows that "the U.S....