SAN YSIDRO, CA – JANUARY 8: Travelers take out their passports before checking in at San Diego International Airport January 8, 2006 in San Diego, California. Beginning on January 23rd, United States passengers traveling by air will be required to show a passport when traveling to Mexico or the Caribbean. Congress is also pushing to require passports when traveling by land or sea to from the United States to Mexico or Canada by early 2008. (Photo by Sandy Huffaker/Getty Images)