You mean the party is allowed to influence the selection of the candidate that will represent them? And put their thumb on the scales against populist candidate

You mean the party is allowed to influence the selection of the candidate that will represent them? And put their thumb on the scales against populist candidates from the fringe with rabidly delusional adherents? One could argue that the GOP primary process would be better off with superdelegates in order to avoid the tendency to nominate fringe weirdos with absurd populist policies.