The ensuing disorder vitiated some of the boost in US credibility that was won on the battlefield, and it opened the way for deeper and more organized resistance during the following weeks.

vitiate (v) 1: corrupt morally or by intemperance or sensuality [syn: corrupt, pervert, subvert, demoralize, demoralise, debauch, debase, profane, deprave, misdirect] 2: make imperfect [syn: mar, impair, spoil, deflower] 3: take away the legal force of or render ineffective [syn: invalidate, void] [ant: validate] – source: Iraq: What Went Wrong