We argue that policy expertise may constrain the ability of politicians to be responsive. Legislators with more knowledge and experience in a given policy area have more confidence in their own issue-specific positions. Enhanced confidence, in turn, may lead legislators to discount opinions they disagree with. Two experiments with Swedish politicians support our argument. First, we find that officials with more expertise in a given domain are more likely to dismiss appeals from voters who hold contrasting opinions, regardless of their specific position on the policy, and less likely to accept that opposing views may represent the majority opinion. Consistent with the proposed mechanism, in a second experiment we show that inducing perceptions of expertise increases self-confidence. The results suggest that representatives with more expertise in a given area are paradoxically less capable of voicing public preferences in that domain. The study provides a novel explanation for distortions in policy responsiveness.