There Actually May Be A Way Forward For (The Still?) Crown Prince in 2020

Believe it or not, the idea of JEB! 2020 may not be as absurd as it seems. Here is the deal. Next year will be make or break for Trump. If JEB! were to enter the race against him later in the year, it seems likely there will not be a big field to dilute his anti-Trump vote as was the case in 2016.  Probably no Little Marco. Pence won't (likely) run as long as Trump remains president, so JEB! might have to contend only with, say Jeff Flake who would not have support with Republican primary voters.  He would get the Poppy sympathy vote.  He would say "Chaos president, I told you so!" Jon Meacham might write a quick glowing clip job biography and position book for him.

If JEB! ran as the only real "protest" vote against Trump, he would be guaranteed at least 30 to 35 % of the disaffected primary vote as the fallout from the Mueller investigation, etc. diminished Trump.  If in the end the GOP then decided, once JEB! is safely the only other viable primary option besides Trump, to throw Trump under the bus in 2020, JEB! will be the one standing to take his place as the nominee.

JEB! would need to enter early enough to dissuade  from running the only real problem for him and
that strategy, and that would be Nikki Haley.  He would need her to stay out and then agree to be his running mate should he be there to take Trump's place.

If something like this were to happen, would JEB! stand much of a chance in the general election?
Probably not, but you never know when a Bush is on the ballot. If you think you saw a lot of Republican voter suppression and fraud in the last midterm election, in places as diverse as Kansas, North Dakota and North Carolina, you can't imagine what you would see if they had a chance to put another Bush in power, and Brett Kavanaugh would be there to help out from the Supreme Court bench if needed.