The rules are a little messy, but the bottom line—as explained by Frontloading HQ—seems to be the GOP’s “unbound” delegates (the closest GOP analogue to Democratic “superdelegates”):
- are awarded in the same proportion as their state’s regular delegates, if their state’s primary or caucus awards delegates proportionally;
- are awarded to the winner of their state’s primary or caucus, if that primary or caucus is winner-take-all.
GOP delegates become truly “unbound” only if they are released by candidates who have withdrawn from the race.
Bustle agrees with this reading of the GOP rules.
So if GOP voters choose Trump (or Cruz), the party leadership will be stuck with that choice.
It’s also worth remembering that the Democratic delegates are awarded mostly proportionally, while the GOP systems in most states more heavily favor the first place finisher. For instance, though South Carolina’s system isn’t purely winner take all, it ended up that way—Trump got 32.5% of the SC votes, but 100% of the SC delegates.
Bottom line: Trump (or Cruz) doesn’t have to win 50% of the GOP popular vote to win the nomination. If one person finishes first consistently, he’s likely to win the nomination on the first ballot.