Kerry could benefit from CIA findings on Iraq, but Bush has his own ammunition. WASHINGTON — The costs and benefits of President Bush's decision to invade Iraq loom ever larger as a potential tipping point in the 2004 presidential election after the release of a definitive CIA study this week concluding that Saddam Hussein possessed neither weapons of mass destruction nor active programs to produce them. The study comes as violence continues to plague Iraq. The situation exposes Bush to a potentially dangerous squeeze: mounting losses on the ground combined with mounting challenges to his original justification for the war....