Abstract

This paper argues that partisan think tanks played an important role in the rapid polarization of American politics that began in the late 1970s. Scholars of polarization conclude that political elites polarized long before their voters or districts did, directing our attention toward causes of elite polarization. I argue that partisan think tanks, particularly the Heritage Foundation, played an important role in elite polarization. Using data on partisan think tank testimony before Congress, newspaper citations and revenue from 1973 to 2016, I examine the time series relationship between partisan think tank outputs and polarization in Congress. I find strong evidence that partisan think tanks are related to polarization in Congress and they relationship is not spurious, but that the correlation is so close that think tanks likely function as a mechanism for other forces polarizing the political system to actualize their preferences. I conclude that researchers should further explore potential causes of both elite polarization and the growth of partisan think tanks.