Mitt Romney obviously did not enter this primary season intending to support Ted Cruz for the Republican nomination. And Ted Cruz probably never wanted his support. But we have come to a time for choosing, and all Republicans now must choose between voting Cruz and surrendering the party to big government social liberal Democrat donor Donald Trump. Today, Romney chose Cruz.

Now, I have had my differences – oh, have I ever – with Mitt Romney. But at heart, Romney is a good, decent and honorable man, and a loyal party man. Cruz is obviously not his first choice any more than Romney was mine, and Romney has previously campaigned in this race for Marco Rubio in Florida and John Kasich in Ohio as part of his stop-Trump campaign. But in Tuesday’s Utah primary, Cruz can win all 40 delegates if he can get to 50% of the vote – and beyond then, only Cruz can stop Donald Trump from getting 1,237 delegates and clinching the nomination before the convention. So today, Romney cast his primary ballot in Utah, one state where he remains unquestionably popular and influential, and he explained on his Facebook page why:

This week, in the Utah nominating caucus, I will vote for Senator Ted Cruz.

Today, there is a contest between Trumpism and Republicanism. Through the calculated statements of its leader, Trumpism has become associated with racism, misogyny, bigotry, xenophobia, vulgarity and, most recently, threats and violence. I am repulsed by each and every one of these.

The only path that remains to nominate a Republican rather than Mr. Trump is to have an open convention. At this stage, the only way we can reach an open convention is for Senator Cruz to be successful in as many of the remaining nominating elections as possible.

I like Governor John Kasich. I have campaigned with him. He has a solid record as governor. I would have voted for him in Ohio. But a vote for Governor Kasich in future contests makes it extremely likely that Trumpism would prevail.

I will vote for Senator Cruz and I encourage others to do so as well, so that we can have an open convention and nominate a Republican.

Romney is being cagey here, and frankly, I doubt that Cruz minds: he’s not endorsing Cruz per se, and he implies that he likes Kasich better than Cruz, but he also makes very clear that voting for Kasich from here on in is just going to help Trump. That should be a real blow to Kasich going forward, given that his natural base of support is mostly Romney 2012 supporters. And whatever you think of Mitt, 2012 proved that he knows what it takes to win a Republican nomination.

Romney expresses his preference for an “open convention,” which may not please those who believe Cruz himself still has a shot to get 1,237 delegates and who suspect the party establishment of wanting another candidate (maybe even Romney!) if Cruz doesn’t get there. For my part, having watched the primaries this far, I don’t think the GOP establishment could organize a game of Candyland, let alone steal a nomination from not one but two contenders who combined are likely to enter July with over 80% of the delegates. But whether you are a Cruz-loving conservative or a Mitt-pining moderate, you have to agree with Romney: a vote for Ted Cruz is the only ticket to stop Donald Trump from destroying the Republican Party and making Hillary Clinton our 45th President.