Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
I develop a model of the relation between the media environment and political obstructionism. I show that when voters are less informed by media, obstructionism becomes a more effective political signal for the minority party. The model thus implies that media change can cause gridlock via signaling; by contrast, the previous literature on causes of gridlock focuses on polarization and other factors. The model also makes several auxiliary predictions consistent with recent trends in U.S. politics.