While I've got a general idea how the elections work, I find it hard to understand that there isn't a notable third candidate in this situation. Wouldn't someone least bit credible - of the caliber Romney or Manchin would've been - have a realistic chance of winning a state or two? And wouldn't that have realistic chance of giving their electors the balance of power, effectively forcing one side to surrender to this compromise candidate?
You'd think there's someone ambitious enough to go for that, even if it is a political suicide failing. Unless it's someone known centrist who has already been independent or switched party.