Interest Group Network Dynamics A dynamic network of amicus curiae brief cosigners across 50 years. Nodes refer to organizations with cosigning ties drawn for each time period. Node size is proportional to degree in the first time period. Node color refers to the SIC division with darker colors indicating higher divisions. Graph layout algorithm is GV’s Neato. Interest group relationships are both created and dissolved over time. A separable temporal exponential random graph model (STERGM) shows that the number ofpartners is important for formation but not dissolution, while industrial homophilyhelps both to make and maintain connections.














