In a previous post, I pointed out that Donald Trump's ability to win the Republican nomination is actually precisely what the post-1968 reforms were intended to allow. Democratic voters wanted McCarthy, who won most of the primaries. The primaries didn't matter, and the elites wanted Humphrey. So, they chose him, riots ensued, Humphrey lost, and the party changed to rules so that the voters got to determine the nominee next time. Now, Republican elites are trying to figure out how to over-rule the voters when the rules were set up precisely to prevent that.
Trump is highly likely to win. Republican elites don't want that now, and will try to figure out how to stop other insurgent candidates in the future. And here's the funny thing about party rules. They can be changed! That's the point. So, what will Republicans do to stop a future Trump? Here are some possibilities:
1) Do what the Democrats did after they got stuck with Carter: introduce superdelegates. Since most Democratic muckety-mucks were unhappy with Carter and never would have picked him in the first place, in the aftermath, they created a new category of delegates: superdelegates. Basically, elected officials and other party types get to vote at the convention for whomever they want. This is why Hillary's lead in the delegates is so 'yuge.' The muckety-mucks in the party don't want Sanders, so they came out for Hillary.
Problem: what if the superdelegates hand the nomination to someone who got fewer delegates from primaries and caucuses? Hillary tried to convince them to give her the nomination over Obama in 2008, but that was doomed because nobody wanted to recreate 1968. That doesn't mean superdelegates are worthless. They can create a narrative of one candidate being toast, e.g., Sanders. That narrative alone can hurt a candidate.
So, will the Republicans create the same kind of system the Democrats imposed after Carter? Maybe, but let's remember that the narrative said Trump was toast all last year anyway, so who knows how much good that will do them.
2) Ballot access games. Here's some fun trivia. What happened to former Senator Robert Bennett from Utah in 2010? If you said that he lost a primary to a tea party candidate, congratulations. Half a point. Bennett didn't lose a primary. The state of Utah has a funny and unique system. In order for congressional candidates to make it to the primary ballot there, the party has to nominate them. Bennett had his name yanked from the primary ballot by party muckety-mucks because they thought he was too far left. Why? Long story, but it doesn't matter. The point is that such a system can exist.
What if getting your name on the ballot for a Republican presidential nomination required having your name sponsored by state party muckety-mucks? You'd still have a primary, so the voters wouldn't be completely locked out, but Trump-like candidates could be barred from the ballot.
As Boss Tweed famously said, "I don't care who does the electing so long as I get to do the nominating."
This seems like a smarter plan. It gives muckety-mucks more control without creating a situation like 1968. Could there be something else? Sure. But one way or another, the Republican Party will almost certainly change the rules after Trump in order to prevent future Trumps from getting this far.