Do you know any of your state’s delegates? Can they be bribed and blackmailed?
I’m thinking the “super” delegates and /or party higher ups.
As I understand it, the delegates are only pledged for the first ballot. At the state conventions, where most of the delegates are actually chosen, the party leadership can pick delegates that will honor their pledge on the first ballot, and then switch to the RNC's preference on all the subsequent votes.
If a candidate has enough delegates to win on the first ballot, he'll get the nomination with no problem. If he comes up any number of delegates short of a first ballot nomination, who knows? Those delegates are no longer pledged to the candidate the voters in the states chose.