In a Trumpless race, either Walker, Rubio, or Jeb! wins. No contested convention.
Cruz benefited by Trump's presence. Without Trump, Cruz IMO isn't even the Huckabee/Santorum of the 2016 race.
Walker would have likely won the Iowa caucuses, so we know what that means in a GOP race - death of a candidacy. However, Walker's gimmick was that he was able to "bridge the gap" between the Establishment and Tea Party. The question is - could he?
Jeb! of course had the money. The question for Jeb! is without Trump in the race, can he win New Hampshire? Jeb! would have got destroyed in Iowa (not as bad as he did, but likely 4th or lower) so IMO he'd have to win New Hampshire. He'd have to win too and not just come in second.
Rubio would have had a similar run as he did. He'd likely surge in Iowa and come in second. The question is does he meltdown like he did in real life?
Rand Paul, Ted Cruz, Ben Carson, etc. etc. wouldn't be much of a factor. Ben may have had the surge he had in October 2015 but it'd end up the same way (I am assuming ceteris paribus - thus things like the Paris and San Bernardino terrorist attacks still happen). Rand Paul couldn't generate the excitement his father did.
IMO it comes down to Florida - if Jeb! won New Hampshire, survived Super Tuesday, and won Florida he'd win the nomination. If Rubio won Florida either he or Walker wins the nomination. Ohio would also be important - Kasich likely drops from the race if he loses New Hampshire.
Bush won IA in 2000 and lost NH
