From a NYT article, based on interviews with insiders, titled "Inside the Republican Party’s Desperate Mission to Stop Donald Trump."
The most interesting revelation is that despite Christie's skewering of Rubio for his robotic scriptedness, after Christie dropped out of the race, Rubio reached out to Christie, to try to get his endorsement. But Rubio bungled it. He left a voice mail that included some sort of assurance that Christie had "had a bright future in public service":
Mr. Christie, 53, took the message as deeply disrespectful and patronizing, questioning why “a 44-year-old” was telling him about his future, said people who described his reaction on the condition of anonymity. Further efforts to connect the two never yielded a direct conversation.Meanwhile, Trump "made frequent calls to Mr. Christie once he dropped out," and "the two met at Trump Tower on Thursday with their wives."
And doesn't that show the problem? It's not just that Trump has his posh real estate and well-practiced socializing skills to butter up useful people, but that Rubio doesn't have anything comparable. He left a voice mail and it was patronizing. He even had the opportunity to script the hell out of the message before calling and he failed to anticipate how his words would affect someone about whom he knew plenty. How is this man supposed to deal with all the many people a President must interact with in all sorts of planned and spontaneous encounters? How can GOP insiders have come up with the idea of everyone coalescing around Rubio? The only argument seems to be to scare everyone into thinking that Trump is a horrible disaster. But Christie's judgment refutes that last ditch scare tactic.
And, by the way, Mitt Romney won't endorse Rubio:
Mr. Rubio’s advisers were... thwarted in their efforts to secure an endorsement from Mr. Romney, whom they lobbied strenuously after the Feb. 20 South Carolina primary. Mr. Romney had been eager to tilt the race, and even called Mr. Christie after he ended his campaign to vent about Mr. Trump and say he must be stopped. On the night of the primary, Mr. Romney was close to endorsing Mr. Rubio himself, people familiar with his deliberations said. Yet Mr. Romney pulled back, instead telling advisers that he would take on Mr. Trump directly.What's wrong with Rubio?!