Roy Moore, U.S. Senate candidate Roy Moore. Photo / AP
The US Republican Party is no stranger to extreme candidates. It has lost eminently winnable Senate races by picking unelectable nominees in recent years.
It voted for the leader of the birther movement and a proponent of banning all Muslim immigration as its 2016 presidential nominee - who won.
But even against that backdrop, Roy Moore is in a class all by himself. It's difficult to overstate how unprecedented Moore's nomination is even for today's Republican Party. And it's difficult to overstate how badly all of this could blow up in the GOP's face.
It's not just Moore's extreme positions; it's also the methods he's been willing to employ and the religiosity - both literally and figuratively - that undergirds his entire political being. While other candidates have said controversial things and espoused extreme positions, none were true-believers on par with Moore.
This is a candidate who:
Was removed from the state Supreme Court for refusing to obey binding rulings - twice - including most recently for refusing to obey the federal legalisation of same-sex marriage
Fomented the President Barack Obama-birth conspiracy theory (which, unlike President Donald Trump, he still hasn't renounced)
Suggested Obama is a secret Muslim in a video released by his foundation
Said homosexuality should be illegal (but clarified that he doesn't think gays should be killed)
Said as recently as this week that certain parts of America are under Sharia law
Called Islam a "false religion"
Said Muslim Representative Keith Ellison of Minnesota shouldn't be allowed in Congress
Suggested 9/11 was punishment for godlessness in America, and said the same of shootings and killings
Denied custody of three children to a woman in a lesbian relationship, calling her lifestyle "an inherent evil against which children must be protected"
While other Republicans have waded into areas that gave GOP leaders heartburn and made unnecessary mistakes as candidates - including bizarre theories about reproduction and rape - they often apologised or backed off in the name of getting elected.
And Trump, for all his extreme policies, is rarely bound by any discernible ideology that can't be altered at a moment's notice.
None of them ran as the kind of unapologetic crusader that Moore is. Moore has shown he'll lose his job for the right cause, including disobeying court rulings that run afoul of his view of God's role in the United States. There will be no controlling or prevailing upon Moore over the next two-and-a-half months before the special election or for the next few years if he joins the Senate; he is a bigger wild card than any of the names mentioned above.
And the fact that he's now the GOP nominee in a lengthy special election could hardly be a worse set of circumstances for Republicans. This is one of just two big races late this year, along with the Virginia governor's race in early November. And you can bet Democrats will try like hell to make it competitive enough to keep Moore in the news until December 12 - even if they don't think they can win.
That will, in turn, force Republicans to explain how this guy fits into their party. Senator Ron Johnson of Wisconsin showed how difficult a trick that can be yesterday, telling CNN that "no two people agree 100 per cent of the time".
That response works fine for policy differences, but not for arguing that Sharia law exists in the US and that Obama is a Muslim.
Republicans got a healthy dose of "Do You Agree With This" when Trump was running.
The whole thing eventually worked out, but it was always an extremely difficult needle to thread - distancing themselves from Trump's most extreme positions while still supporting him.
In Moore, Democrats have almost a caricature of a Deep South Republican whose views would have been outside the mainstream even decades ago.
Before Trump, Moore was the kind of candidate Republicans might have disowned or tried harder to beat in the primary.
Today, they have to bearhug him and hope against hope that it will all be okay.