So , as can be seen, The Dem House surplus was largely in states where incumbent House Democrat Senators were running for reelection. In fact, if you add up the states of CA, NY, IL, MA, VA, WA and NJ, you'll see that Dem House surplus in those states was 10.3 million. Trump won none of these states in the 2016 election and still won, so the point about Dems getting 10 million more votes than Republicans has no bearing on the 2020 election. Trump wasn't even on the ballot in these elections. There were Democrat surpluses in the three states than I mentioned PA, WI and MI, but all 3 had Democrat incumbent Senators on the ballot and Mr Trump only needs to win one of those states in 2020 in order to win. --With a lot more Republican Senators up for reelection in 2020 than Democrat Senators, we should see a stronger Republican presence in those states that have those incumbents and this will affect House races as well.