In the 1950s, political scientists feared that weak parties in the U.S. threatened democratic accountability. Today, many political scientists argue strong, ideologically extreme parties distort representation. Undoubtedly, things have changed, but why? Several possible culprits exist, including partisan gerrymandering, primary elections, the ideological realignment of the electorate, and changing congressional procedures. We will cover the possible explanations and try to decipher what explanation, or combination of explanations, is most convincing. While we evaluate the arguments for why polarization has increased we will also debate the merits and drawbacks of strong parties at the elite level. Finally, we will examine to what extent polarization among elected officials and activists reflects polarization in the public. Students will also engage in collaborative research projects aimed at understanding polarization in the context of the 2020 election. The goal is to share information from these research projects publicly in order to provide voters with information about elections in real time.