For almost three years now, Republican strategic thought has been roughly divided between two schools. One, represented by Jeb Bush, Marco Rubio, and to a lesser extent Rand Paul, accepts the notion that the party must improve its performance with minority voters, without sacrificing its command of the white vote, in order to remain competitive in presidential elections. The other, represented by Ted Cruz and Scott Walker, rejects this premise.

These Republicans hew to the theory, expressed numerically by RealClearPolitics analyst Sean Trende, that making inroads with minorities is not important. The key to winning, they believe, lies with activating a large block of the white electorate that has stood on the sidelines, but would find a natural home in a Republican party if it were led by someone who could channel the political mood of the white working class.

Donald Trump is currently performing the hugely important political task of adjudicating this intra-GOP debate. Running as a Republican, Trump has made both factions’ goals—and the overarching goal of winning the presidency—more elusive. But by stitching together all the performative qualities Republicans have nurtured on the right over the years—pomp and property worship, xenophobia and anti-establishmentarianism—he’s also showing us what it takes to stir the passions of these missing white voters. Most Republicans, quite sensibly, are horrified by what they see.

In years past, Republicans didn’t think of Trumpism as a liability so long as Trump was outside the tent pissing further out. When Trump was busily whipping up reactionary sentiment, indulging birther conspiracies, Republicans didn’t see a “jackass”—they saw an opportunity. They recognized his appeal to a segment of white voters, and concluded it could be put to good use, so long as he marshaled his followers into the Republican electorate. They didn’t call him a media creation back then—they sought his endorsement.

Trump is now inside the tent, pissing everywhere. He threatens to neutralize the potential of these voters, or train them as a weapon against their own natural party, while bulldozing inroads to minorities. By placing xenophobic immigration politics at the center of the campaign, he’s made it practically impossible for Republicans to convince minorities that there's a softer side of the GOP. And by condemning him so vocally, his Republican critics are reminding Trump’s supporters of everything they don’t like about the Republican party.

A nationwide Washington Post/ABC poll shows Hillary Clinton running ahead of Jeb Bush in a head-to-head matchup by a healthy but malleable 50-44 percent margin—the kind of margin that might close in a world where Bush manages to both increase the GOP's share of the Latino vote and bring more members of the white working class along for the ride. But Trump’s primary candidacy is poisoning the GOP’s relationship with both sets of voters.

Republicans are therefore casting about for ways to extirpate the Trump phenomenon. Ideally a serious scandal or the financial consequences of his impolitic outbursts would end his candidacy, and quickly.

But party officials have refused to ask him to leave the race, let alone force him out. To mistreat Trump is to invite him to launch a third-party candidacy, and if he were to run as an independent, as he routinely threatens, the GOP’s narrow path to the presidency would close completely.

That same Washington Post/ABC poll also poses a three-way race between Clinton, Bush, and Trump. In that scenario, Clinton’s vote share drops by only three percent. Bush’s drops by 15. Altogether, Clinton winds up with 47, Bush with 29, and Trump with 19. The Bush and Trump shares combined are larger than Clinton's, which lends credence to the missing white voter theory. The problem is there's no way to encapsulate their individual appeals in a single candidacy.

Any Republican running against Clinton and Trump would have to choose between doubling back and fighting Trump for his share of the white vote, or jettisoning the Republican platform and competing with Clinton for Democratic votes. Which is another way of saying the GOP’s only option would be to lose. Even at two or three percent, Trump’s impact on the Republican candidate would be fatal.

If Trump were truly the media’s creation, as nervous Republicans like to claim he is, his candidacy would be a fleeting nuisance to more viable Republicans, and if he drops out early, the damage he’s doing might reverse itself. But Republicans can’t plausibly claim that what’s happening is a purely media-enabled stunt. They’ve recognized Trump’s draw on certain white voters in the past. They’ve tried to capitalize on it. He’s just showing them what it takes to do it for themselves.