Parties‐as‐networks is an emerging approach to understanding American political parties as decentralized, nonhierarchical, fluid systems with porous boundaries of a wide array of actors. Parties‐asnetworks include interest groups, social movements, political consultants, and advocacy organizations, in additional to the usual suspects of elected officials, party officials, and citizen‐activists. This approach ameliorates several deficits of the traditional, tripartite view of parties in government, in elections, and as organizations. The authors apply the parties‐as‐networks approach using data from surveys of delegates at the 2008 Democratic and Republican national conventions. Analysis of delegates’ memberships in a wide variety of organizations demonstrates that Democrats have larger networks than do Republicans; Republican networks tend more toward hierarchy than do Democratic networks; and the content of Democratic networks is tilted toward labor and identity organizations, while Republican networks are more populated by civic, religious, ideological, and professional organizations. The parties‐as‐networks view is a potentially revealing source of insight on the dynamic evolution of party coalitions. Theoretically, approaching parties as networks deepens the understanding of how intermediary institutions matter to the functioning of democratic politics.