Trump seems to make every play and speech directly to his base. Some people say it is 35%, some say 45%, but is that enough to get him another term? Can he rely on Dems drifting away from the Dem candidate if he/she is not the one they wanted as they did in 2016? What do you think?
First Democrats didn't drift away. Hillary Received 89% of the Democratic base vote vs. 88% of the Republican base vote Trump received. 90% being average. Obama received 92% of the democratic base vote in 2012 vs. 93% of the republican base vote for Romney. More republicans deflected Trump than Democrats did Clinton. Trump won on the independent vote. This brings me back to your question, can Trump win with his base only? No way is the answer. What percentage of the electorate that make up each party's base vote changes all the time, it's dynamic.
In Nov 2012, Democrats made up 35% of the electorate, Republicans 30%. Independents made up 33%. The democrats had a built in 5 point advantage. In Nov of 2016 that advantage was chopped to three points 30% Democratic, 27% Republican. Independents shot up to 40%. Trump winning independents 46-42 over Hillary with 12% voting third party was the deciding factor. Not democrats drifting away from Hillary.
I peg Trump's base at 40%. In 2016 independents disliked Hillary much more than Trump although half disliked both major party candidates. The trick for 2020 is for the Democrats to choose a candidate that isn't as disliked by independents as much as Trump. that seems almost impossible, but the Democrats managed to do just that in 2016. Now in 2020 the Democrats have the advantage that a lot of independents have soured on Trump. I don't think he'll be able to match that 46% from independents he received in 2016 in 2020. That is unless the Democrats nominate another Hillary Clinton type candidate.
Another thing is in 2016, Hillary was the well known candidate with all the baggage. In 2020 that candidate will be Trump. Independents knew how Hillary would govern, being well known, perhaps too well known and said no way. They voted Trump and he's in the White House today. Independents didn't know how Trump would govern. Didn't know much at all about him. He was an unknown. He won't be in 2020. You'll have role reversals then.
No, looking at the numbers all around, no way can Trump win reelection. The Democratic Party is still the larger of the two major parties. Because of Trump's unsavory antics and his raunchy personality, they have regained their lost numbers. Today they stand at 32% of the electorate with the Republicans at 26% That advantage is even higher than it was in 2012. Independents don't like Trump, with a decent candidate that can attract independent voters, I wouldn't be surprised if that candidate received 55% of the vote.
There's a couple of candidates on the Democratic horizon if nominated that might let Trump back in the game. So the ball is in the democrats court. 2020 it the democrat's election to lose, but then again, so too was 2016.