Wal-Mart has been a frequent target for many political causes in the United States including the labor movement, environmentalists and health care advocates. In Mexico, it has drawn a new enemy — supporters of presidential candidate Andres Manual Lopez Obrador. About 80 supporters of the candidate stormed several Wal-Marts in Mexico City, blocked cash registers and threw around merchandise because of Wal-Mart's alleged support of conservative President-elect Felipe Calderon. Wal-Mart, which denies it supports Calderon, is Mexico's largest retailer.