We examine the trade-offs between unanimity and majority voting under incomplete information. While conventional wisdom suggests that unanimity leads to higher reform rejection rates and higher total transfers compared to the majority rule, we show that this does not always hold when the proposer lacks perfect knowledge of responders’ acceptance costs. Using a simple theoretical model, we identify conditions under which uncertainty leads the proposer to adopt different bargaining behaviors, sometimes resulting in a higher probability of reform approval under unanimity rule, and sometimes yielding higher total transfers under majority rule. Our findings inform the current EU debate on replacing unanimity with majority voting and provide nuanced insights into the arguments advanced by each side.