During a sustained period of heightened polarization, majorities of both Republican and Democrat voters have retained their party registration. According to a recent study from the Pew Research Center, only 9% of those who affiliated with the Republican Party or leaned Republican in September 2018 now identify as Democrats or lean Democratic, and the same goes for the opposition party: only 9% of those who identified as Democrats or leaned Democratic two years ago now identify with the Republican Party.
The shifts that have occurred have been along education lines. According to Pew, white college-educated voters have become more Democratic, while white voters without a college degree have grown more Republican. This may continue in 2020, as white voters without college degrees – who played a big part in electing President Donald Trump in 2016 – double down on Mr. Trump, and white college-educated voters, most of whom live in the suburbs and disapprove of him, double down for the Democratic ticket.