Timothy Stanley, a conservative, is a historian and columnist for Britain's Daily Telegraph. He is the author of "Citizen Hollywood: How the Collaboration Between L.A. and D.C. Revolutionized American Politics." The opinions expressed in this commentary are solely those of the author.

(CNN) By the end of the CBS debate Saturday night I was left feeling simultaneously disgusted with the Republican Party and more confident about its future. Why? Because all the rhetorical violence on stage indicated that the GOP has a breaking point. Reaching it and going beyond it is the path to electoral success.

Call it creative destruction.

The debate began on a dignified note as the candidates paid their respects to Justice Antonin Scalia, who died this weekend. There seemed to be consensus in the group that Obama should not appoint a replacement during his last months of office, while each showed off their knowledge of the Constitution and the best conservative legal authorities around.

It was downhill after that.

The theme of the evening was lying. Each candidate took it in turn to accuse the other of being a liar on one subject or another -- like a party game at Festivus...

Almost everyone accused Ted Cruz of lying, a reputation that he gained not just through the tactics he deployed in Iowa against Ben Carson but also on the basis of his alleged evolution on immigration. Cruz told the debate audience that Donald Trump had glazed over his past position on abortion -- which prompted Trump to call him "the single biggest liar" on the stage.

And Trump might just have turned the debate upside down when he said that George W. Bush was not only wrong about the war in Iraq but that he lied about the presence of weapons of mass destruction in the country. Jeb Bush fought back but he never does it very convincingly. He grins when Trump is mocking him and he stutters when he launches a counter-attack.

I can imagine Jeb having nightmares about these debates: seeing Trump's head spinning around the bed, saying, "You're weak, you're weak, you're weak..."

How to process Trump's assault on the reputation of George W. Bush? It goes beyond what's normal in U.S. politics -- but then Trump isn't normal and his success is rooted in his refusal to be. Folks like his honesty and seem to value it above the actual content of his arguments. But this time he may have gone too far.

Trump twice stated that George W. Bush hadn't kept America safe because 9/11 had occurred on his watch. That's terrible logic -- like blaming a fireman for the flames he's trying to put out. To be fair, Marco Rubio's attempt to pin the blame on Bill Clinton was just as morally perverse, but politically a bit more sensible: at least Republicans hate Clinton, whereas they love George W. Bush.

By the way, the correct answer is that 9/11 wasn't caused by either Bush or Clinton -- it was caused by Islamist fanatics. That the collapse of the Twin Towers should be politicized in this manner is really quite awful.

How Trump's attack on the Bush family will play out is difficult to judge. At present, polls suggest that Trump enjoys a double digit lead in the state. But George W. Bush enjoys a 77% favorability rating among local Republicans.

South Carolinians have strong religious and military values that might not sit well with the language or temperament that Trump put on display.

On the other hand, some viewers might appreciate the candidate's extraordinary courage. And others might feel that the audience was ganging up on him, given the booing coming his way - although Trump seems to draw energy from other people's disdain.

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Nevertheless, Jeb Bush's attempt in his closing statement to frame the debate as a question of reckless radicalism vs. experienced leadership was smart. Trump was almost a parody of himself. If nothing else, his constant interruptions irritated. He looked visibly uncomfortable when asked who, if anyone, he was prepared to take criticism from.

I'm guessing the answer to that question lies in the mirror.

It is possible that this debate re-established some red lines in the Republican Party. A candidate, like Trump, can probably get away with being protectionist, isolationist and anti-big money. But can a candidate get away with being vague on the abortion issue or downright insulting about a previous president who, at the very least, led the country through the nightmare of 9/11 with tremendous dignity?

If the answer to those last two is "no" then Trump may slide in South Carolina. The question is, who will overcome him? Kasich played it positive but landed no blows. Rubio was good on Reagan; Carson need not have shown up. The winners were surely Ted Cruz and Jeb Bush.

How ironic, given how poisonous the Bush association was supposed to be, that Jeb is now counting on affection for his family to save his candidacy.