One year ago, literally to the day, I was having lunch with a friend of mine who is very high up in a prominent progressive political organization. I posed a question: “What if Obama’s biggest political legacy, the thing he’ll be most remembered for aside from being the first Black president, hasn’t happened yet? What if his biggest legacy is the complete destruction of the Republican Party at the national level ― sending them the way of the Whigs?”

My friend laughed and thought this hypothesis was fanciful, but I insisted that it just might be the case. I wasn’t sure how it would happen, but my sense at the time was that for a variety of reasons, Obama had driven the Republican party to such dysfunction that it could simply never recover.

The biggest political story at that moment was the inability to find anyone who was willing to be Speaker of the House — which is usually a job politicians really WANT — and the second biggest issue was the persistence of Trump’s candidacy beyond the summer. Both seemed to me (and to many other observers), like symptoms of the same root problem: a Republican party gone mad.

I did not think, at the time, that Trump would win the nomination. I thought he would force a more traditional nominee so far into crazy town, particularly on immigration, that the nominee would be toast. Then Trump won the nomination, and I felt more correct in my assessment of the party’s future than ever.

As Hillary faltered over the past few months, however, I began to fear that perhaps I’d been wrong. Maybe this country wasn’t what I thought it was, what I experienced on the trail in 2008. But I held out hope that once the debates happened, once the country could see the real Hillary and the real Trump, there would be an inflection point.

Now the debates are over, and that inflection point does seem to have happened. It’s too soon to say for sure that Hillary will win, and every Democrat/progressive/American who cares about maintaining a constitutional, representative democracy needs to spend the next three weeks like we’re ten points down. But if we stay focused and united, I think we may tonight have witnessed the true beginning of the end of the Republican party, a wound inflicted that will ultimately kill the patient.

I’m not exaggerating.

Here’s the thing: A lot of Republicans – both elected officials and regular rank and file folks – are horrified by Trump’s comments about not accepting the election result, the first candidate to say so in the history of the country. But a lot of other Republicans really believe the election is so rigged that he shouldn’t just accept the results. That means if Trump loses, one group will accept it and another, encouraged by the candidate himself, absolutely won’t. Those who accept will dismiss the rejectionists as cranks; those who reject will view those who accept as sellouts.

In essence, one group will want to continue functioning as a political party within the United States government, and the other will be saying the entire government is illegitimate and probably be calling for secession or overthrow. That’s not a division which can easily be papered over, and even if Trump does concede, the rejectionists will say the only reason he lost is because the “accept” camp stabbed them in the back.

Of course, having a significant portion of the country that rejects the legitimacy of the federal government is very dangerous. The fallout of the Republican split will likely have wide ranging ramifications, both good and ill, the nature of which we have not yet imagined. And if Hillary loses, God forbid, all of this supposition becomes moot.

But if Democrats, progressives and pro-democracy independents can hold together for the next few weeks, we will likely view October 19 as the night the split in the Republican party became too wide and deep for it to ever recover. And if that’s the case, we’ll be entering a new chapter of American political history.