The crazy thing is, that might actually happen. Trump isn't particularly popular with either Democrats or Republicans right now. The only difference is that Dems almost universally despise him, while he's created quite the rift in the GOP. It's been many moons since a sitting president failed to win his party's nomination for a second term. I know it's happened before, probably close to 200 years ago. ***just looked it up. It was Franklin Pierce. He's the only previously-elected Prez who lost in the primaries. A couple of others failed to secure their respective party's nominations, but they were initially VP's of deceased presidents who ascended to the White House without being actually elected.