WASHINGTON – President Barack Obama stepped up his criticism of Arizona's controversial immigration law Wednesday, calling it "misdirected" and warning that it has the potential to be applied in a discriminatory fashion. Speaking at a joint news conference with Mexico's President Felipe Calderon, Obama called for overhauling the nation's immigration laws and said that can't be done unless Republicans support it. The controversy over the Arizona law, which would make it a state crime to be in the country illegally, hung over Calderon's visit. Both leaders oppose the law, with Obama directing the Justice Department to review it for possible...