We study how party factionalization affects government reforms. We develop an accountability model where the incumbent party is internally divided into factions which can sabotage the implementation of a reform. Voters are uncertain about whether a reform is needed and how divided the party is. In equilibrium, a united party is valued by the electorate because of its effectiveness. In turn, this might lead it to produce unnecessary reforms. We show that factions can improve voter welfare precisely because voters want to punish internal division. However, the welfare effects are non-monotonic: moderate levels of factionalization optimally balance the trade-off between reform effectiveness and equilibrium incentives to choose the correct policy. These findings offer novel insights into the strategic implications of factional dynamics and their impact on governance efficiency.