The Role of the Democratic and Republican Parties as Organizers of Shadow Interest Groups

This article advances a new theory to explain the relationship between political parties and interest groups. Among the as yet unanswered questions that I resolve are: (1) why many politicians -both Republicans and Democrats - develop a reputation for "party loyalty" despite the parties' inability to employ any meaningful sanctions against politicians who deviate from the party line; (2) why candidates for public office run in contested primaries when running as an independent generally would be a less costly mechanism for getting on the ballot; (3) why the two major U.S. political parties continue to attract resources from contributors and to inspire loyalty among various groups despite an apparent decline in party strength as shown by split-ticket voting, contested primaries, and a growing lack of ideological cohesion within party platforms.