WASHINGTON (Reuters) - Secretary of State Hillary Clinton on Wednesday forcefully defended her handling of the September 11 attack on the U.S. mission in the Libyan city of Benghazi and denied any effort to mislead the American people. The attack by armed militants that killed U.S. Ambassador Christopher Stevens and three other Americans threatens to stain Clinton's legacy as secretary of state and could cast a longer shadow should she decide to make a White House run in 2016. ...