Indications are that suburbia, traditionally Republican for decades, is changing.
Political observers see two areas of suburbia–the inner suburbs near major urban areas, and the outer suburbs, much further away and closer to rural areas.
The inner suburbs have become more racially and ethnically diverse, and are tending toward the Democratic Party, as in California’s Orange County as just one example in the Midterm Congressional Elections of 2018.
Meanwhile, the outer suburbs are seemingly very loyal to the Republican Party, since there is far less diversity further away from the cities, and reflect the conservative values common to rural America.
The fact that the inner suburbs are tending Democratic should be a good sign for the party in the Presidential Election of 2020, but whether what happened in 2018 is a trend, or an exception, is hard to assess at this point.