What happened on the debate stage Wednesday night was unprecedented. Donald Trump had a solid debate until one key question.
"Do you make the commitment to absolutely accept the results of this election?" asked moderator Chris Wallace.
Trump's answer mattered. Here's why. There have been 34 presidential debates in U.S. history and no candidate has ever refused to say they'll accept the results until now.
"I will look at it at the time," Trump said. "What I've seen is so bad," he added referring to allegations of widespread voter turnout.
Trump versus Hillary Clinton is breaking all the rules. Trump's refusal to say he will accept the results blew up Twitter. Even die-hard conservatives like Laura Ingraham disagree with Trump's approach, but some Trump supporters are siding with Trump.
One woman tweeted, "there's another option. It's called the 2nd Amendment. If you think we will tolerate this you're mistaken."
Then there are the pundits who say what Trump said has happened before.
They point to 2000 when Al Gore did not concede and challenged the election results in Florida, but that was because the vote was so close. It triggered an automatic recount. Gore ultimately conceded and accepted a Supreme Court decision that stopped the counting. He lost Florida and the presidency by 537 votes.
If Trump wanted suspense, he's definitely created it. Historians say this debate will be remembered for that single moment. Trump did tweak his position on Thursday, he say she will accept the results, "if he wins."