If the Republican establishment really wants to stop Donald Trump before he secures the nomination, they should ask Mitt Romney to promptly shut up.
Mitt Romney entered the fray with an anti-Trump speech that actually helped Donald Trump. Romney followed that up by recording a robocall for Marco Rubio in Florida and by personally joining John Kasich on the campaign trail in Ohio.
Bear in mind, that was only a week ago.
Just a week after appearing alongside him in Ohio, Romney has now recorded a robocall for Ted Cruz in which he explicitly instructs Republican voters not to support John Kasich.
“I’m calling to ask you to join me in supporting Ted Cruz for president this Tuesday in the Utah Republican caucuses. This is the time for Republicans across the spectrum to unite behind Ted,” Romney says in the call targeting Utah voters. "And at this point, a vote for John Kasich is a vote for Donald Trump.”
I imagine Republican voters who either haven't decided who to support or were leaning toward supporting Donald Trump will almost certainly support him now. There is no coherent opposition or alternative message to Donald Trump. "Anyone but Romney" didn't work out any better in 2012 than "anyone but Trump" will in 2016.
It's possible Donald Trump will not reach the required number of delegates to secure the nomination before the Republican convention, but what then? Does the GOP deny him the nomination if his next closest opponent has nowhere near enough?
I don't think so.
In addition to the monumental amounts of opposition research Democrats will unload on Donald Trump this year, we also have an unintentional ally: Mitt Romney. Romney has produced excellent fodder that Democrats can deploy in districts where, at the very least, certain Republicans may be persuaded to cross over or not vote at all.