Overview: 2012/03/12 Headlines: 16 Afghan Civilians Massacred by U.S. Sergeant; 21 Palestinians in Gaza Die in Israeli Air Strikes; Memorials Mark First Anniversary of Japan's Nuclear Crisis; Santorum Wins in Kansas, Romney Takes Wyoming; AFL-CIO to Endorse Obama; Dozens Killed in Syria as Kofi Annan Leaves Without Deal on Truce; U.S. Drone Strikes in Yemen Kill 25; 100,000 March in Largest Bahraini Pro-Democracy Rally; Egyptian Military Court Acquits Doctor in Virginity Test Case; NAACP Seeks United Nations Help to Fight New Voting Laws in U.S.; Coalition of Immokalee Workers End Six-Day Fast for Fair Food; Nobel Prize-Winning Chemist Sherwood Rowland, 84, Dies;$