Voting for Trump and the electoral mosaics of US metropolitan areas: Exploring changing patterns of party support by neighborhood

The socio-spatial structure of US metropolitan areas is the foundation of their electoral geographies: political parties and their candidates draw their support from separate groups within society whose spatial segregation is reproduced in voting patterns. As a consequence, when there are changes in a party's support base these should be reflected in its electoral landscape. The extent of such changes is explored here in analyses of precinct-scale voting patterns at the 2008, 2012 and 2016 US presidential elections across 373 SMSAs. Eight types of electoral mosaics are identified using a cluster analysis of those SMSAs and their distribution explored in the context of their socio-economic and -demographic characteristics. Of the eight types, the SMSAs in four showed little change in the voting profiles of their precincts between 2012 (Obama's second victory) and 2016 (when Trump won in the Electoral College but lost the popular vote); SMSAs in the other four types experienced considerable change, with many more rustbelt SMSA precincts delivering a Republican landslide at the latter contest.