TV Shows Weakened Iraq Defenses in Tikrit By NICOLE WINFIELD .c The Associated Press CAMP AS SAYLIYAH, Qatar (AP) - U.S. Marines were operating Sunday near the dusty desert town of Tikrit, a power center for Iraq's Sunni Muslim tribes that is believed to be the one of the last strongholds of fighters loyal to President Saddam Hussein, U.S. Central Command said. A task force from the 1st Marine Expeditionary Force was within about 35 miles of the town, approaching from the south, having ``moved north along Highway 1 to Tikrit from Samarra,'' said Lt. Mark Kitchens, a Central Command...