This article presents the first comprehensive analysis of the role of war chests in U.S. Senate elections. Using data on races from 1980 to 2000, I demonstrate the effect of an incumbent senator's war chest on a campaign. War chests do not deter strong general-election challengers and have an insubstantial or insignificant effect on primary elections, challenger spending, and other electoral variables. Also, war chests are not raised in anticipation of a tough electoral battle but are instead the result of money left over from the previous campaign.