WASHINGTON - Former Secretary of State Colin Powell endorsed Sen. Barack Obama, D-Ill., for president on Sunday, criticizing his own Republican Party for what he called its narrow focus on irrelevant personal attacks over a serious approach to challenges he called unprecedented. Powell, who for many years was considered the most likely candidate to become the first African-American president, said in an interview on NBC’s “Meet the Press” that he was not supporting Obama because of his race. He said he had watched both Obama and his Republican opponent, Sen. John McCain of Arizona, for many months and thought “either...