OCEANSIDE - Leo Diaz, a young Marine from Texas based here at Camp Pendleton, went to Iraq full of faith in the president who sent him. Today, he is burdened by the horror of what he saw and shocked at what he calls President Bush's ``frat boy'' mentality in starting the war. ``I show up. I'm proud. I'm looking forward to do my part,'' said Diaz, 22, whose father, uncle and grandfather served in the military. ``Turns out, we find no weapons of mass destruction. People hurt, killed.'' Diaz voted for Bush in 2000. But now he plans to vote...