STOCKTON-Richard Pombo, clad in a beige polo shirt and jeans, is leaning back in a folding chair, his trademark ostrich-skin boots under a table. He's bantering with a reporter and an aide, and appears at peace. But he really isn't. Pombo, a seven-term Republican congressman, is in the tightest race he has seen in more than a decade to hold on to his once-safe seat -- and he knows it. Despite the comments of his Democratic opponent, Jerry McNerney, and the accumulated evidence of national voter surveys, Pombo thinks his troubles have nothing to do with Iraq, ethics or the...