This volume explores the conflict between two forces: party polarization and party factionalism. The major change in America’s two political parties over the past half-century has been increased polarization, which has led to a new era of heightened inter-party competition resulting in stronger and more cohesive parties. At the same time, elections, particularly primaries, often reveal deep internal factional divisions within both the parties, and the 2020 election was no different. The Democratic coalition typically pits moderate or establishment candidates against progressive activists and candidates, while the Republican Party in 2020 was, at times, polarized not only between moderates and conservatives but between those willing to criticize President Trump and those who would not. How did these two opposing forces shape the outcome of the 2020 election, and what are the consequences for the future of American party politics and elections?