This dissertation examines how social networks and interpersonal recruitment influence individuals' political participation. Using survey data, the study reexamines some of the central propositions that the scholars of social movements and political participation have made. The findings challenge some of the propositions and clarify others.

First, despite strong selection effects, interpersonal recruitment does causally affect individuals' participation in politics, especially in non-electoral forms of participation such as protests, community politics and lobbying government officials. Interpersonal recruitment's effect, however, is not constant across individuals. Interpersonal recruitment affects those who are not likely to participate in politics on their own more than it affects people who are already likely to participate in politics. However, interpersonal recruitment often does not target the former, and concentrates instead on those with high participation potential.

Second, contrary to what previous studies have claimed, little evidence suggests that strong ties are more effective than weak ties as a channel for interpersonal recruitment. Ties formed in civic associations, however, serve more effectively than other kinds of ties for recruiting protest participants. I conclude that the content of relationships and the identity shared by two people, not tie strength, form the basis for interpersonal influence in political activism.

Finally, a network's influence on political activism depends on the salience of politics in the network and on the actors' efforts to influence others in the network. Political activism, in other words, does not flow through social networks without explicit mobilization efforts through political discussion.