The last 25 years have witnessed growing partisan polarization and intensifying party conflict. Some evidence indicates that partisanship has supplanted race as the main social cleavage in America. Anecdotally, we see it as people de-friend and block each other on social media. This session will focus first on political polarization and main factors contributing to political polarization: increasing economic inequality and the growing divisions along educational and geographic lines that impact social identity, culture, and political preferences. This provides the context in which the 2018 elections are occurring. The second part of the session will focus on the factors that influence the outcomes of congressional elections: partisanship, gerrymandering, incumbency effects, strategic behavior by candidates, campaign finance, and voter turnout. The final part of the session will look at and explain forecasting models that predict the outcomes of the elections.