5 minutes ago NEW YORK - Anxiously watching President Bush (news - web sites)'s convention, Democratic leaders are urging John Kerry (news - web sites) to step us his attack on the Republican incumbent before eroding approval ratings become a serious political problem. The candidate and his beleaguered staff are being flooded with advice, much of it contradictory. Some party officials want Kerry to criticize the president's for sitting out the Vietnam War in the Texas Air National Guard. Others say that would draw unwanted attention to accusations about Kerry's combat experience. Democrats have seen Bush erase the gains that...