The incipient anti-Trump movement has already had its ups and downs, but the PAC seems to have had some success in Wisconsin, where it spent about $2 million in a state in which the anti-Donald vote coalesced around Ted Cruz, a Southern-fried tea party evangelist who was not necessarily a natural fit in the North Country. The establishment might not have been able to win in 2016, but destroying is easier than building in politics, and Miller, speaking to me for POLITICO’s “Off Message” podcast, expressed a ravenous appetite for Trump destruction.

I asked him how bad a Trump candidacy would really be for the Republican Party ? and would Clinton’s email troubles propel the Manhattan mogul to victory, as Trump has suggested?

“Hillary would beat him from jail,” Miller said. “I’m telling you. That’s how unpopular he is. It’s crazy.”

Crazy is one word for it. A friend working on a down-ballot race in North Carolina had thrown a Trump question into a poll last week. “Twenty-three fave, 69 unfave was the verdict on Trump” statewide, he told me. “Could he improve that over the course of the general after five months of people having to watch Hillary on their TV? Would [traditional Republicans] end up kind of holding their nose and moving back towards him? Sure, but how many?” The friend speculated that Trump might not even crack 35 percent favorability in North Carolina, a state Mitt Romney carried narrowly in 2012.

More ominously for Trump, Miller says many of the people associated with the Stop Donald movement have no intention of stopping their efforts even if he’s able to secure the nomination over a surging Cruz. Miller says he would eagerly work for a third-party conservative who rises to challenge Trump, even it means handing the White House to Clinton, a person he finds personally “loathesome.”

Miller predicted that Our Principles PAC ? funded by the billionaire Ricketts family of Chicago and HP executive Meg Whitman ? would consider backing “Fantasy Independent Candidate X” as a way to salvage the core GOP brand so that mainstream Republicans like endangered Ohio moderate Sen. Rob Portman aren’t wiped out in a fall anti-Trump wave.

“You know, if there’s a viable third-party candidate, I could see us supporting that,” said Miller, a Colorado native who cut his teeth at the Republican National Committee. “I don’t know that there’s going to be a lot of support for … a Republicans-for-Hillary thing, which I couldn’t be a part of. So, if there’s a third party [candidate] that people could point towards even if it was a protest vote ? yeah, I could see that.”

At the moment, the PAC, led by Romney campaign veteran Katie Packer, is trying to raise more cash and assessing how to spend the money it has left. “We’re looking for states ? Indiana, California, Nebraska ? where we can keep his number below 1,237 and then, you know, then it’s kind of up to the Cruz folks to win it on the floor,” he added.

The more interesting question, Miller noted, is what happens to Republican organizations around Washington. “American Crossroads, and, you know, things of that ? groups of that nature. ... all the Koch groups, you know, what do they do? It’s hard to see them having much support for Trump. So I think their money then moves towards the Senate and to the Save Paul Ryan campaign.” (Here, Miller was alluding to the growing alarm in GOP circles that Republicans could even lose the House, and thus the speakership, with Trump at the top of the ticket.)

Miller has moved on, but he’s clearly still bummed out by Bush’s defeat ? even though he now realizes that his boss had virtually no chance of winning despite raising more than $100 million, hiring a blue-chip staff (including Miller and veteran GOP message man Mike Murphy to run his super PAC) and clearing the field of fellow establishment scion Mitt Romney. “When we looked at our numbers, about three-quarters of the voters who did not support Jeb in the Republican primary [listed] their top reason was either 1) ‘dynasty’ or 2) ‘not angry enough,’” he told me. “We were running the asylum for a while, and, like, the inmates have now taken over. ... We’ve got major issues.”

Miller, a gay Republican who supports same-sex marriage (but also backs Cruz, who vigorously opposes it) has had a disorienting, dispiriting whipsaw of a year that has him admitting publicly something he once would have considered unthinkable: He’d root for a Clinton victory in a head-to-head matchup with Trump. “I think that she would be maybe our worst president,” he told me with a rueful chuckle. “But Trump is a danger to the Republic.”

Major damage has already been inflicted on the party, whatever happens at the Republican convention or in November, Miller says, because Trump has tethered the GOP to a cement-shoes conception of the electorate that relies on older white voters while repulsing blacks, Hispanics and social moderates. “There’s only so much more white juice to squeeze out of the orange there,” Miller told me. “People are like, ‘You know, I’m really worried if there’s a terrorist attack, Trump would beat Hillary.’ And I’m like, ‘Is the terrorist attack like a Zika virus that just kills all the brown people?’”

Miller’s struggle to bring diversity to the GOP has been personal, not just political. He came out in 2007 and has often had to work for politicians who didn’t back gay marriage, or even admit that discrimination against gays, lesbians and transgender people was an issue that needed to be addressed. Bush, whom Miller admires, was a middle-ground social conservative. “I believe in traditional marriage,” Bush wrote in an op-ed opposing last summer’s Supreme Court decision legalizing gay marriage. “I believe the Supreme Court should have allowed the states to make this decision. I also believe that we should love our neighbor and respect others, including those making lifetime commitments.”

A short time later, Bush was staffing and offered the job to Miller backstage at a Washington hotel before he was about to make a major speech at the high-stakes Conservative Political Action Conference gathering, when the new public face of his campaign approached him with some information. “Look, I’m gay,” Miller recalls telling Bush. “I’m open about that. If that’s an issue for you, no worries. I’m not going to tell anybody about it. But then we should just stop this conversation here.”

Bush smiled and offered an “I’m good” glance. “And then he paused, and then he started to go into a longer answer,” said Miller. “I said we don’t need to belabor the point. He started to spit out a longer answer, and about eight words in I just cut him off.”

A few months into his new job, Miller was faced with another challenge that illustrates the difficulty gay Republicans have reconciling their identities with a party base that more or less rejects them. Bush, in an effort to appease social conservatives who weren’t too fired up to begin with, backed Indiana Gov. Mike Pence’s bill allowing businesses to refuse service to LGBT customers on religious grounds. Miller wasn’t crazy about his boss’s position, but he soldiered on.

“Honestly, I didn’t feel that strongly about the Indiana issue personally ? and I don’t know that it would have mattered even if I did,” he said. “The Indiana bill, you know, sure, I think I would’ve probably supported something differently than that. But, you know, look, when you’re running on one of these campaigns, you’ve got to pick the person that you think is best suited to be president. ... As a moderate Republican, there are shrinking numbers of candidates.”

Bush, Miller said, was a sensitive boss ? in an earnest, not-quite-hip-dad kind of way.

Jeb and I were talking about Hobby Lobby ,” Miller said ? referring to the Supreme Court case that raised constitutional questions about the employer’s rights to deny contraception to employees.

Bush turned to Miller and asked how to answer if a reporter pressed him on the case ? then interrupted himself to say, “Well, I assume there would be some gay people that work at Hobby Lobby.”

“Sir,” Miller replied. “It’s a craft store.”