The Midwest is increasingly the critical region in American politics. It is the only region in which large numbers of states flipped from Obama to Trump in 2016, and in the 2018 Midterms the Midwest was once again the site of many of the most interesting results. For me, this region includes Minnesota, Wisconsin, Iowa, Illinois, Michigan, Indiana, Ohio, and Pennsylvania. I don’t include agricultural red states like the Dakotas or Missouri, which have voted Republican in every presidential election since 1996.

Despite their shift toward Trump in 2016, many of these Midwestern states demonstrated a willingness to support Democrats in 2018. In the Senate, Minnesota, Wisconsin, Michigan, Ohio, and Pennsylvania, Democrats held the line against Republican challengers, losing only in Indiana. In governor races, Democrats retained Minnesota and Pennsylvania, and took Wisconsin, Illinois, and Michigan from the Republicans. The Republicans were able to defend their hold on Iowa and…