This study examines how variation in nonpartisan legislative staff capacity shapes state legislators' reliance on external policy actors. Detailing a historical account of the state legislative development, I argue that cycles of institutional weakening, alongside bouts of professionalization, have produced inconsistent and significant disparities in internal capacity across the states. In environments where nonpartisan staff is limited, external organizations, interest groups, and policy networks may play an out-sized role in supplying legislative language and policy frameworks. Conversely, stronger nonpartisan capacity may enable legislatures and individual legislators to develop policy in-house and exercise greater autonomy. As we renew our attention to state legislatures, it is important to understand this relationship as we evaluate which groups and individuals have influence and under what conditions.