There is no such thing as a “populist-conservative” movement. Yes, there are populists who mistakenly think they are conservative and actual conservatives who voted with the populists simply to defeat the lizard queen last year. Maybe some of those conservatives will stick with Trump in 2020 if the Dems are stupid enough to do what @JodyH says and nominate someone as detestable as Warren. Then again, maybe not if you consider the opinion polling in AL having Trump pegged at just 46% approval.
Finally, the character of leaders absolutely influences what they do in office. Virtually EVERY organization that trains leaders lists character as a key attribute for effectiveness. Trump’s character is a big reason why many of you will be paying 30% higher healthcare premiums in 2018. I’d have thought that 16 years of Clinton-Obama polices would have settled that misguided notion.