To enact a policy, a leader needs votes from committee members with heterogeneous opposition intensities. She sequentially offers transfers in exchange for votes. The transfers are either promises paid only if the policy passes or paid up front. With transfer promises, a vote costs nearly zero. With up-front payments, a vote can cost significantly more than zero, but the leader is better off with up-front payments. The leader does not necessarily buy the votes of those least opposed. The opposition structure most challenging to the leader involves homogeneous committees. Our results provide an explanation for several empirical regularities.