Trump's victory in 2016, and his consistent support in polls from about 40-45% of the population, shows there is a significant audience for his hard-edged message on immigration and demographic change more broadly. But there is also a clear cost. In effect, Trump's bruising racially-infused nationalism is forcing the GOP to trade support among younger voters for older ones; secular voters for the most religiously conservative, especially evangelical Christians; diverse voters for whites; white collar whites for blue-collar whites; and metro areas for non-metro areas. Since Trump's emergence Republicans have consolidated their control of small-town, exurban and rural communities. But that has come with significant losses for the GOP inside metropolitan areas even in red states, like Texas and Georgia.
The trade Trump is imposing on the GOP was apparent in 2016 and enormously intensified in 2018.
In 2016, Trump lost 16 of the 20 states where foreign-born residents constituted the largest share of the population and won 26 of the 30 states where they represent the smallest shares. Even in the relatively more diverse states he won, he lost the vast majority of the big urban centers where immigrants and other minorities generally concentrate. Overall, Trump lost 87 of the 100 largest US counties to Hillary Clinton by a combined margin of over 15 million votes, according to calculations by the Pew Research Center.
Trump offset these losses by amassing the largest margins for Republicans in decades in small-town, exurban and rural areas. In 2018 House races, Republicans suffered only very modest losses outside of metropolitan area districts. And they gained three Senate seats in states with large populations of white voters who are rural, blue-collar, or evangelical Christians: North Dakota, Indiana and Missouri. But the party was routed in metropolitan House seats that contained significant populations of minorities, immigrants, singles, college-educated white voters, or all of the above.
After sweeping losses in suburban districts from coast to coast, the GOP under Trump has been almost completely exiled from the dynamic metropolitan areas that account for the nation's vast majority of job growth and economic output.