FALLUJAH, Iraq — At the western entrance to the Iraqi city of Fallujah on Tuesday, Muamar Anad handed his residence badge to the U.S. Marines guarding the city. They checked to be sure he was a city resident, and when they were done, Anad said, a Marine slipped a coin out of his pocket and put it in his hand. Out of fear, he accepted it, Anad said. When he was inside the city, the college student said, he looked at one side of the coin. "Where will you spend eternity?" it asked. He flipped it over, and on the...