That's the claim of one Rachel Bitecofer, a political science professor at Christopher Newport University. Now, I would normally be disinclined to take such a claim seriously, but Bitecofer does have a bit of a track record to brag on. Very early in the 2018 election cycle, she was predicting the Democrats would greatly benefit from the phenomenon of "negative partisanship" (people are most partisan about how much they hate the other party). The model she based on this approach expected the Democrats to gain 42 seats; they gained 40.
You may recall that in my attempt to give comprehensive coverage to forecasting models of the 2018 election, I did cover Bitecofer's predictions a bit. At the time, I thought they seemed too optimistic on the Dems, but in the end she turned out to be very close to the mark.
So what does she say about the 2020 elecction? From her NY Times op-ed:
"Motivated by the threat posed by the Trump administration, casual Democratic voters, especially college-educated women, have been activated since Mr. Trump’s election and will remain activated so long as the threat he presents to them remains. And the complacent Democratic electorate of the 2010 and 2014 congressional midterms as well as the 2016 presidential election is gone (for now). It has been replaced by a galvanized Democratic electorate that will produce the same structural advantage for Democrats that manifested in the 2018 midterms.
The surge won’t be uniform. Democrats will win big in more urban, more diverse, better-educated and more liberal-friendly states and will continue to lose ground in other states like Missouri. Although Mr. Trump may well win Ohio and perhaps even Florida again, it is not likely he will carry Michigan, Wisconsin and Pennsylvania in 2020. Look at the midterm performance of statewide Democrats in those states. And his troubles with swing voters, whom he won in 2016, will put Arizona, North Carolina and perhaps even Georgia in play for Democrats and effectively remove Virginia, Colorado, Nevada and New Hampshire from the list of swing states.
In short, the 2020 presidential election is shaping up as a battle of the bases, and the Democrats’ base is simply bigger. When their demographic advantage combines with an enthusiasm advantage and heightened party loyalty fueled by negative partisanship, they hold a significant structural advantage."
OK then! The implication here is that any reasonably good Democratic candidate should be able to beat Trump. Now about that reasonably good Democratic candidate.....