There are headlines going around setting up that Newt Gingrich attacked Mitt Romney for his speech against Donald Trump, but his interview on Fox and Friends is raising an important point about the dynamics of a convention which has no first-ballot majority. And even if he didn't realize this, he's pointing out another way Trump might yet be stopped.
Here's the video. Gingrich calls Romney's speech nasty and vitriolic against Trump, and that it was. The former Speaker however isn't saying that Romney was wrong to say it. Rather, he's saying that if you wanted to win the nomination on a later ballot, you wouldn't say that.
I think we understand why he'd say this. Consider a likely scenario in which no candidate gets a majority. We might see Trump and Ted Cruz each at 35-40% of the delegates, with Marco Rubio and John Kasich splitting the rest. Even though these delegates would not be bound to every ballot, one might reasonably expect that many of these delegates would still like their guy.
Any deal brokered on the floor of the convention in Cleveland would have to be made with the actual, selected delegates. Gingrich is assuming that Trump's delegates are Trump backers, Cruz's delegates are Cruz backers, and so on. But as we saw last cycle in some states, that's not always the case.
Ron Paul managed to hijack the delegations of some states in 2012. Paul supporters made deals with other candidates in caucuses and were pledged to other minor candidates, right up until those candidates were no longer running. They were then free to back who they wanted: Ron Paul. Further, Ron Paul supporters were able to hijack the Nevada system and get Ron Paul delegates on the floor to vote Ron Paul, even though Romney won that state by every measure.
Delegate selection will be a critical fight. While Trump's delegates will be bound to him for one or more ballots, they won't necessarily actually be Trump supporters. How the specific RNC delegates are chosen is going to be a very important matter, and one where the establishment might have a huge leg up. Different states have different procedures for this.
Imagine if Trump delegates turned out to be Cruz or Rubio supporters after the first ballot! Stranger things have happened, and I hope the good guys are on the ball about this.