In the repeated interactions of a legislative session, legislators develop working relationships that can be used in the pursuit of legislative goals. I develop a theory of influence diffusion across a legislative network of relations based on strategic actors building relationships in order to increase legislative success. Building on sociological theory initially developed by Granovetter, my research indicates that it is the weak ties between legislators that are the most useful in increasing legislative success. I test my theory using state legislative data from eight state legislatures, along with a second analysis of the US House of Representatives. Empirical analysis provides consistent support for the notion that weak ties lead to legislative success.