How does uncertainty affect the process of policy reform? Our investigation identifies two types of uncertainties, one at the electoral level and another at the implementation level. When voters abstain from the electoral process, electoral uncertainty emerges. Implementation uncertainty arises whenever the politician is unable to guarantee a positive outcome from a policy implementation. Using a political agency model where two groups of voters delegate to a politician the decision to implement reform or maintain the status quo of the economy, we show that both implementation uncertainty and electoral uncertainty affect policy implementation in different ways. Implementation uncertainty might introduce disagreement between voters about the (ex-ante) convenience of implementing the project. On the other hand, with electoral uncertainty in the political system, political power may be detached from the group’s relative size, thus linking it to the citizens’ probability of being the decisive vote. In short, a highly disciplined minority group could gather enough political power to impose their preferred policies over a less disciplined majority group.