I don't think it really matters who the Rat nominee is. They are moving so far left and are so over the top hysterical they make POTUS Trump look calm, statesman like and reasonable. The liberal bubble in the media and in the big urban centers only represents 40% of the country at best. The Pubs have at least 40% supporting them. The other 20% can't possibly think radical leftists would be better than a populist, nationalist.
Trump wins if he runs.
The Pub party is a different story. If they fail to keep their promises (repeal obamacare, tax cuts, tax reform, deregulation, conservative social policy) will begin to see declines in 2018 and will probably lose the House & maybe the Senate in 2020. I know I wouldn't vote for any of them if the election were held today.