Two things: I’m not sure Trump will run in 2020 and the only way he could be beaten if he does, is if the winning has not been happening for a while.
The thing about trump is that, though he does not articulate his points well, his points ARE genius. We have entered the first period of political sanity in my lifetime.
President Trump does what is right for the USA, not himself. I have rarely seen that before and certainly not for many years.
If Trump has 4 Winning years he may decide to go back to his private billionaire life.
In that case Romney would have to beat out Mike Pence.
Not going to happen.
Not run in 2020? Don't be ridiculous.
The only thing that could prevent Trump from running would be if he dropped dead at the Resolute Desk.
Being a former NYer, I have followed Trump for many years. He's a big thinker and this is his chance to leave his mark on the world.
BTW, 1 year has already passed and he is just getting started. In 3 more, he will be hitting his stride.
Believe me, Trump is now unstoppable.