Intra-party sabotage is widespread and can be detrimental to political parties. Despite its pervasiveness, little is known about the conditions facilitating sabotage — typically associated with factions’ opposing interests — and how parties react to contain it. I study a model of elections between two parties where factions can devote their resources to campaign for the party or to undermine each other. Each party redistributes electoral spoils among factions based on their internal rank — a noisy signal of their resource allocation. The model identifies conditions under which sabotage can be limited, and shows how parties’ internal organizations change to maximize the chances of winning the election. Results show that intra-party and inter-party competition are substitutes: as the electoral stakes increase, factions invest fewer resources into sabotage and devote more resources to promote the party. In equilibrium, parties adopt a winner-take-all incentive scheme when factions’ probability of ranking higher is increasing in campaigning effort, otherwise rewards are set to zero. When factions in the same party have different ideological preferences and parties choose policy platforms, in equilibrium the saboteur can be rewarded with policy concessions.