Only 2 members of Congress is an independent. They are different than previous parties and in some ways weaker. For example, you do not find a handful of party leaders controlling the party and politics. Today you have a stratarchy - different levels of party organizations in conjunction with candidate organizations, partisan office holders and a public that is generally partisan, but can turn on the party if made unhappy. Interest Groups as Organizations Interest groups are NOT simply people who hold similar views.
Interest groups ARE organizations that represent people who hold similar views.
Disturbance theory Assumes government is responsive to group demands. If group threatened or affected by policy, they will organize to try to change policy. Mobilization to fulfill their political interests. Theory of Selective Incentives People only engage in collective action when they receive a selective incentive. A selective incentive is one that is a private good.