The decline of the power and influence of national parties and the rise of candidate-centered politics have made state and local governments increasingly responsible for administering elections and distributing political power. Because the two major parties enjoy more financial and popular support, third parties have had relatively little success at the federal and state level.

The candidate-centered nature of political campaigns has shifted the role of state parties to one that is more consultative and facilitative than in the past. Despite a decline in party machines across states, the degree of interparty competition within states remains high, as evidenced by the 2002 and 2006 state legislative elections. From campaign finance regulation to the administration of state political primaries, state governments remain highly influential in the nomination process.

The trend toward professionalized campaigns has been intensified by the increasing prominence of interest groups in the legislative process. Interest group activity in the states has increased tremendously in the last fifty years. Although the American public tends to distrust them, interest groups fill important informational, mobilization, and financial roles in the political process.