It’s not just the Republican establishment that’s starting to coalesce around Ted Cruz. It’s the putative outsiders, too.

On Wednesday, former presidential candidate Carly Fiorina endorsed Cruz. “Ted Cruz is a fearless fighter for our constitutional rights,” she said in a statement. “Unlike the status-quo political class in D.C., Ted Cruz didn’t cower when he got to Washington—he stood unequivocally for the American people.”

Fiorina allying with Cruz makes some superficial sense—one outsider endorsing another. But it probably makes the most sense to see Fiorina’s endorsement of Cruz as a statement of disgust with Donald Trump, and a realization that the only candidate with any serious chance of stopping him is the Texas senator.

Throughout her presidential run, Fiorina positioned herself as an outsider—a corporate executive rather than a party creature. That wasn’t exactly true. She had run for Senate as a Republican in 2010 and been an adviser to John McCain in 2008, and as McKay Coppins notes, party insiders encouraged her to run, thinking that it would benefit the party to have a woman and business leader in the race. Running as an outsider was shrewd in a year when Donald Trump, Ben Carson, and Ted Cruz were all doing the same, but it wasn’t enough, and she dropped out in early February.

Politically, Fiorina and Cruz aren’t obvious allies. She spent much of her adult life in California, where she seems to have been a fairly standard-grade pro-business conservative. During the presidential campaign, she moved to the right, especially on abortion. But that’s still a long way from Cruz’s hardnosed devotion to the Constitution and the Bible. Nor is she likely to bring a great number of votes to Cruz—if she commanded those, she might have gone farther in the campaign.

Fiorina’s endorsement likely flows from two major sources. The first is animus. Trump was, to be blunt, a huge jerk to Fiorina throughout the campaign. “Look at that face! Would anyone vote for that? Can you imagine that, the face of our next president?” he told Rolling Stone. The pair tangled in debates, which Fiorina gladly going on the attack against Trump. When he criticized her record at HP, she was happy to dismantle his own record. Given how personal things got, it was hard to imagine her ever backing Trump.

The second is strategic. Fiorina is in the same boat as people like Senator Lindsey Graham, who has detested Cruz as a colleague and once said he’d be as bad a nominee as Trump. Graham hasn’t taken the step of formally endorsing Cruz yet, but he’s now happy to tell any news camera in sight that Cruz is preferable to Trump. None of these people seem exactly happy about Cruz, but they see the Republican field dwindling to a two-man contest, and they simply can’t bear to imagine Trump winning it.

Adding insult to injury, Fiorina made the endorsement at a rally in Miami, the hometown of Marco Rubio. Once the great hope of establishment Republicans—the same people who nudged Fiorina into the race—Rubio has faded to practically nothing. In Mississippi and Michigan on Tuesday, he failed to crack the 15 percent threshold needed to win delegates. His last chance is to win Florida, though even then it’s hard to see where his path to the nomination lies. Despite pleas from some Republican strategists to “splinter” the vote, in order to deprive Trump of the 1,237 delegates he needs to win the nomination, Cruz has been campaigning aggressively in the Sunshine State. Of course, when has Cruz ever heeded the advice of Republican Party strategists?