Assuming Trump is the GOP nominee...will 2nd place in the primaries endorse him?

[NewYorkExpress]

Did Randall Terry and John Wolfe endorse Obama? I don't think so...

My *guess* is that at least one person will be challenging Trump in the primaries who will have enough of an organization to get ballot access in more than half the states.  I think even a McMullin could pull that off.  That's my guess, but I wouldn't call it a sure thing....

I think there will be several challengers. Kasich, Cruz, Martinez, McMullin and maybe even Romney.

I don't think Martinez runs... I think McMullin could run again, but he's more likely to get somewhere as an Independent, and Cruz would only run if he loses in 2018, otherwise he's better off staying in the Senate. Kasich is the only one on that list who is definitely running.