Damon Linker’s latest column on the travails of the Republican Party at the hands of Donald Trump hits on a tremendously important truth. Linker says that if Trump wins tonight in South Carolina, it

will not only strongly indicate that he’s likely either to win the nomination orprevent the nomination of anyone else prior to the GOP convention this summer. It will also portend a tumultuous future for the Republican Party, regardless of who ends up as the nominee in 2016. A party with such a large bloc of voters who diverge so sharply from the party’s organizing ideology is either a party that will need to significantly change its ideological direction — or one on the verge of breaking apart.

He says that Trump’s outburst in last weekend’s debate, in which the candidate said that the Iraq War was a disaster, and that George W. Bush “lied” to drag America into the war, was a bright red line. The conventional narrative told by antiwar critics is that the Bush administration told itself (and the American public) a story it wanted to believe, to justify war on Iraq, engaging in a massive — and massively consequential — episode of confirmation bias. That is bad, but it is not the same thing as deliberately lying for the sake of starting a war. That particular slander has been common on the far left — until the leading Republican candidate for president in 2016 uttered it onstage in a presidential primary debate.

Unthinkable! But Trump went there. Linker’s Week colleague Michael Brendan Dougherty (side note: what a great pair of columnists those two are) recounts what happened next:

So yes, Trump’s anti-Bush comments crossed a line, but they were in the right direction: away from Bushism. And oddly enough, instead of letting Jeb carry the anchor of his brother’s administration in that debate, Rubio stupidly volunteered to do it for him. “I just want to say, at least on behalf of me and my family, I thank God all the time that it was George W. Bush in the White House on 9/11 and not Al Gore,” said Rubio. This got a wildly enthusiastic response from the partisan Republicans in the hall. What did everyone else in the country think? Jeb also tried to avoid any substantive confrontation on his brother’s record, by claiming that it was unsporting of Trump to attack his family members. Does the public like the kind of cronyism that forbids us to judge the last Bush presidency merely because that family has threatened us with another one? Is this what the Republican Party wants to sell during its primary as it prepares to face a Clinton? I doubt it.

Amen, brother! As shocking and as offensive as Trump’s “Bush lied” remark was, it was not as shocking and as offensive (to me, anyway) as the continued refusal of the Republican Party’s leadership to concede that the Iraq War was a mistake, and to talk about what lessons it has learned from that disaster. If they cannot and will not discuss it, how on earth are we to trust them not to lead us into another such catastrophe? Here’s Linker, on the larger political point here:

Within the party’s establishment, the unwillingness ever to concede an error, rethink a policy commitment, or adjust an item on the agenda feels like a show of strength, tenacity, and resolution that will always be rewarded by voters who supposedly crave flamboyant displays of toughness. But from the outside, it can look like blind obstinance, rank stupidity, a cowardly denial of reality, and an unwillingness to shoulder a rightful share of the blame. Which brings us back to Trump. What voters hear when he rails against the stupidity of the country’s political leadership, the incompetence of George W. Bush, and what he likes to call the complete disaster of American policy in Iraq and the broader Middle East is a man willing both to face the ugly truth that they themselves perceive and to call out those who refuse to acknowledge it. If he gets a little carried away in countenancing some unsavory conspiracy theories, that’s a forgivable offense. Certainly more forgivable than Republicans failing to take even the least bit of responsibility for what they’ve done, and failed to do, while holding positions of power.

That’s exactly right. And it is why the ugly, barbaric, crude, demagogic Donald J. Trump, at times like these, is doing his country a favor. The Republican Party created this monster. He is Nemesis for the hubris of the George W. Bush years and all that has followed. They deserve him. Whether America does is a different question.

(And by the way, to the extent that Bernie Sanders lays into Hillary Clinton for the sins of the Democrats in doing Wall Street’s bidding under her husband’s presidency and beyond, he is serving a similar constructively destructive role in his party. I invite all my Democratic readers (and everybody else, but especially them) to watch this 2009 episode of PBS’s Frontline, called “The Warning”, or read the transcript. It is damning to the Democrats as well as the Republicans in Congress. I wish Bernie would start talking about Brooksley Born, and what official Washington did to her, bipartisanally.)