To enact a policy, a leader needs votes from committee members withheterogeneous opposition intensities. She sequentially offers transfers in ex-change for votes. The transfers are either promises paid only if the policypasses or paid up front. With transfer promises, a vote costs nearly zero.With up-front payments, a vote can cost significantly more than zero, butthe leader is better off with up-front payments. The leader does not neces-sarily buy the votes of those least opposed. The opposition structure mostchallenging to the leader involves either a homogeneous committee or a com-mittee with two homogenous groups. Our results provide an explanationfor several empirical regularities: lobbying of strongly opposed legislators,the Tullock Paradox and expansion of the whip system in the U.S. Houseconcurrent with ideological homogenization of parties.