Most of the war's long-term downside won't be clearly traceable to the war. For example, terrorists don't typically publish treatises about their formative influences. In contrast, the war's short-term upsides—cheering throngs, discovered and destroyed chemical weapons—are often visible and viscerally gratifying. This asymmetry biases democracy toward anti-terrorism policies that feel good at the time but can be killers in the long run.
In theory, the hope for correcting this bias lies with reflective, far-seeing leaders who will perceive the cosmic implications of the various possible war-on-terrorism strategies and illuminate them via edifying speeches, thus steering us away from policies that feel good but are actually bad. Why don't I feel optimistic?
(Update 4/10/03: Since writing this piece, I've published a piece in the New Republic describing how the Bush administration could have achieved all its stated goals in Iraq—including regime change through war if necessary—by working through the United Nations.)