Polarized interest groups compete to influence a decision-maker through monetary contributions. The decision-maker chooses a one-dimensional policy and has private information about his ideal point. Competition between interest groups under asymmetric information yields a rich pattern of equilibrium strategies and payoffs. Policies are systematically biased towards the decision-maker's ideal point and it may sometimes lead to a "laissez-faire" equilibrium where the decision-maker is freed from any influence. Either the most extreme decision-makers or the most moderate ones may get information rent depending on their ideological bias. The market for influence may exhibit segmentation with interest groups keeping an unchallenged influence on ideologically close-by decision-makers. Interest groups refrain from contributing when there is too much uncertainty on the decision-maker's ideology and when the latter is ideologically too far away.
