Republican presidential candidate Ted Cruz on Friday picked up the endorsement of Mitt Romney, the party's 2012 nominee, as the Republican establishment seeks to slow the march of front-runner Donald Trump ahead of more state primaries next week.
Both Democrats and Republicans are set to hold primaries Tuesday in Arizona and Utah, while Democrats alone will caucus in Idaho. Republicans also hold a convention in American Samoa.
Cruz, a conservative firebrand who represents Texas in the Senate, has collected the second-highest number of delegates in the Republican contest so far and is the only candidate to have defeated Trump multiple times in state primaries that have taken place since February 1.
While many of his Republican Senate colleagues make no secret of their personal dislike of Cruz, some have concluded he is the lesser of two evils.
Former Republican candidate Lindsey Graham, previously a Cruz critic, endorsed him earlier this week.
The comparatively moderate Ohio Governor John Kasich also remains in the race, but Romney decided he wasn't formidable enough to topple Trump.
Writing on Facebook on Friday, Romney said "a vote for Governor Kasich in future contests makes it extremely likely that Trumpism would prevail."
For his part, Trump didn't appear phased by Romney's Cruz endorsement:
"Failed presidential candidate Mitt Romney, the man who 'choked' and let us all down, is now endorsing Lyin' Ted Cruz. This is good for me!" he tweeted.
Trump leads the delegate count with 678 of 1,237 needed to secure the nomination; Cruz has 423 and Kasich has 143, according to an accounting by Bloomberg.
In the Democratic race, former secretary of state Hillary Clinton goes into Tuesday's polls with 1,614 delegates versus 856 for Vermont senator Bernie Sanders, according to realclearpolitics.