Convergence or Divergence? Do Parties and Outside Groups Spend on the Same Candidates, and Does It Matter?

There is a good deal of discussion currently among political scientists about the nature of political parties and the impacts of changing party–group relations. Are so-called outside groups promoting extreme candidates and, thus, contributing to polarization? Or perhaps, party-allied groups follow the party’s lead and support the same candidates the party supports. We view parties as extended party networks (EPNs) and examine the campaign spending practices of formal party organizations (the House congressional campaign committees) and some of the groups that are seen as allied with each party and some we expect to be outside each party’s network. We analyze the levels of congruence and divergence in party and group spending in the 2014 House elections. We find that most nonparty groups support the same candidates favored by the party with which they most identify, and very few are outside each party’s EPN-supporting candidates who are challenging the party’s picks. [ABSTRACT FROM AUTHOR]