But, of course, demographics are not destiny — they never have been. There are problems in these projections for Democrats, too:

1. The population of eligible voters is less diverse than the U.S. population overall (the latter is about 39 percent non-white, while the pool of potential 2020 voters is projected to be about 33 percent non-white).

2. In 2020, almost half the electorate (44 percent of voters) is projected to belong to a demographic (white and working class) that now overwhelmingly backs Republicans. These voters were about equally split between the two parties as recently as the 1990s.

3. Non-white people are a huge swath of the electorate in some states, but not in many others. In 2020, white people are projected to make up more than 80 percent of the electorate in 23 states, according to this study. Non-white people are expected to be more than 40 percent of the electorate in just six states (California, Georgia, Hawaii, Maryland, New Mexico and Texas) and Washington, D.C., by that point.