Answer: At precisely the moment that nothing other than weak whataboutism could answer for the debacle last week. After watching Donald Trump supporters, fired up at a rally by the president and his supporters (especially Mo Brooks and Rudy Giuliani), march down Pennsylvania and smash their way into the Capitol, Republicans reached for any excuse they could find.

It was Antifa, except it wasn’t. After that, it was no one complained when Black Lives Matter rioted, except Republicans did and still do, loudly. The cops didn’t arrest and prosecute rioters, except they actually did — and the Department of Justice at least tried to force those cases into federal court when local prosecutors refused. And it goes without saying that Capitol Hill is fully within federal jurisdiction, unlike the riots in the cities — and that the insurrection in this case targeted the federal government and the constitutional process of formalizing election results, the very core institution of our federal republic.

At what point, the Wall Street Journal’s Gerard Baker scolds, do conservatives and Republicans embrace their core values — objective truth and accountability? Baker so far sees almost nothing but newly minted moral relativists all the way down:

In the wake of last week’s violent incursion at the U.S. Capitol, President Trump’s supporters have been working overtime on the moral-equivalence shift.

Sure, the president’s claims of a stolen election are dubious, but they’re nothing worse than what Democrats and the media did for four years in promoting the false Russia-collusion story, refusing to acknowledge the legitimacy of the Trump presidency, and trying to destroy it.

Yes, the violence at the Capitol was terrible, but so too was the mayhem perpetrated by Black Lives Matter and antifa in dozens of American cities last summer.

OK, the president’s language and affect are autocratic, but what about the rapidly encroaching illiberalism of the tech and media giants that is narrowing the boundaries of free speech?

All legitimate objections. And there have been and will be many times when all these alarming instances of progressive extremism should be thoroughly exposed and condemned.

But now is not that time.

Now is the time when conservatives especially need to look beyond the frustrations of what often seems like an unlevel moral playing field and acknowledge an unequivocal, unqualified truth: The president’s behavior last week was uniquely and unforgivably iniquitous. And the decay goes deeper. It cannot be excused by citing counterparts on the left.

With moral relativism being the order of the day, who needs an alternative to the real moral relativists in the Democratic Party and the progressive movement? At least they have more experience at it and employ it on a broader philosophical basis. For Republicans these days, especially in MAGA circles, it’s used more as a dodge, sometimes dressed up as an “own the libs” strategy, and almost always argued with sexual denigrations about those who hold to principle.

It’s one thing when this is just tactics — reprehensible, but fixable. The problem with the GOP is that this is all it is any more. It’s all tactics and no principle. That explains how two-thirds of its House caucus and a half-dozen Republican senators could vote to overturn election results in two states despite having zero constitutional authority for such an action, while its leadership promised or at least strongly suggested that their tactics could deliver the mob a victory. All they had to do is “fight,” and the victory would be theirs, Trump and other Republicans urged the mob.

That doesn’t all just get explained away by Donald Trump either. There weren’t 121 Trumps on the House floor voting to throw out Arizona’s election results, which would have disenfranchised millions of voters and disregarded state sovereignty in a manner that might have made Woodrow Wilson and FDR blush. This is the end result of a party leadership abandoning principles and governing philosophy. Power becomes the only value, and moral relativism the only possible excuse for what follows.

Not for the first or last time these days, I’m reminded of this scene from A Man for All Seasons. Perhaps this should be on everyone’s viewing list, because there’s a funny thing about knocking down all of the institutions to own the devil … there’s nothing left to protect you when the inevitable happens.