Gerrymandering is effective because of the wasted vote effect. "Wasted votes" are votes that did not contribute to electing a candidate, either because they were in excess of the bare minimum needed for victory or because the candidate lost. By moving geographic boundaries, the incumbent party packs opposition voters into a few districts they will already win, wasting the extra votes. Other districts are more tightly constructed with the opposition party allowed a bare minority count, thereby wasting all the minority votes for the losing candidate. These districts constitute the majority of districts and are drawn to produce a result favoring the incumbent party.