Which theory is closest to the truth?

[mencken]

Sources:
https://www.realclearpolitics.com/epolls/other/president_trump_job_approval-6179.html
https://www.washingtonpost.com/graphics/2017/local/virginia-politics/governor-exit-polls/?utm_term=.d9d1aa544717

(By the way, distinguishing between likely voters, registered voters, and adults is simply begging the question; if these numbers are going to be constantly brought up as a forecast of how the midterms/presidential election will go, then they ought to at least reflect who will be participating in those elections; do not compare apples and oranges)

[IceSpear]

It's obviously above 40% with likely voters, though I'm not sure I'd say "well above."

[Cactus Jack]

The former. The weird truth is that, despite his frankly inexplicable support among Republicans, nobody really likes Trump outside of his hardcore groupies. In fact, he's objectively pretty unlikable.

[Person Man]

The exit poll had Northam winning by 3-5 with 42% approval. Northam won by 9. If there is a very strong correlation, which may be reasonably assumed, that gives us 38 or 39 for Trump. That is where he was on election day last year. Given just an average candidate, he will probably do how he should have done last year had the Obamacare and Comey letter didn't break...about 4 points worse..enough to lose FL, NC, AZ, WI, MI, and WI and to sneak by in OH, TX, GA, and IA...though GA would have been so close.

[Antonio the Sixth]

Option 4: polls are inherently noisy.

[Fuzzy Bear]

How does Trump get to be, in fact, more popular than his approval numbers?  A clue to this lies in a recent Rasmussen Poll:

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Such a phenomenon would lead such a candidate to have lower approval ratings than normal because a number of their own party would view such a President as "half a Republican".  The important thing is that no one views Trump as some sort of crypto-Democrat.  This means that, policy-wise, he can really offer something to everybody.

What keeps Republicans in line for Trump is that everything is tilted to the RIGHT.  This is like Nixon in 1972; he took some positions that are, in retrospect, considered liberal, but Nixon was an authoritarian Republican who took a position and looked RIGHTWARD.  That's what Trump is doing.  "Tilt everything to the right!" was, I believe, a directive for Nixon's re-election campaign.

So while Trump positions himself in a place different than conservative orthodoxy may dictate, he does tilt his issue positions to the right.  He's seen as looking to the right.  This keeps conservatives who may not "approve" of him in line, and why they'll "approve" of him in the way that counts; by voting Trump/Pence in 2020. 

[🐒Gods of Prosperity🔱🐲💸]

Something to consider though I haven't looked at the numbers enough to know if relevant here:

People who vote in an election are more likely to have an opinion when it comes to approval vs disapproval of the president. That is in an electorate which generally reflected the national split, you'd be likely to have both higher approvals and higher disapprovals from an exit poll than you would from a poll of another sort.

[BlueSwan]

Option 4: polls are inherently noisy.

[Pericles]

538's likely voter filter has Trump at only 39.1%.