the fragmented nature of the US political system creates multiple access points for pressure groups, and some groups such as the NRA and AIPAC are commonly viewed as having a significant and consistent impact on policy.
major policy changes on issues such as civil rights, abortion and gay rights have been brought about through pressure group activity.
the close involvement of key groups in the passage of important legislation, e.g the role of phRMA in health care reform.
the decision in the supreme court case of citizens united increased the ability of pressure groups to influence campaigns- such as super PACs.
the proliferation of professional lobbyists and the high price for their services suggests that the right kind of pressure is successful... and in high demand.
the ever-increasing cost of elections and the consequent need…