The victim of this morning’s pile-on is Kentucky Senate candidate Alison Lundergan Grimes, who was asked in an editorial board meeting whether she had voted for Barack Obama in 2008 and 2012. Grimes hemmed and hawed a bit, obviously scared to say Yes. That isn’t too surprising — when you run as a Democrat in a red state (just as when you run as a Republican in a blue state), you spend a lot of your time explaining why you aren’t like the national party and its leaders. But some people are outraged, including Chuck Todd, who said on Morning Joe (with a look of profound disgust): “Is she ever going to answer a tough question on anything?…I think she disqualified herself. I really do, I think she disqualified herself.”

No question, Grimes botched this badly, and she should be able to answer a question as simple as this one. But this affair gets at the odd set of unspoken rules that dictate what gets designated a “gaffe” or a serious mistake, and what doesn’t.

The problem isn’t that one party gets treated more harshly than the other does. There are plenty of Republican candidates who have gotten pummeled for their “gaffes.” Rather, the problem is the standard that reporters  use, probably unconsciously, to decide which gaffes are worthy of extended discussion and which ones merit only a passing mention, a standard that often lets GOP candidates get away with some appalling stuff.

For instance, when Iowa Senate candidate Joni Ernst flirted with the “Agenda 21″ conspiracy theory — a favorite of Glenn Beck, in which the U.S. government and the United Nations are supposedly conspiring to force rural people in Iowa and elsewhere to leave their homes and be relocated to urban centers — national pundits didn’t see it as disqualifying. Nor did they when it was revealed that Ernst believes not only that states can “nullify” federal laws they don’t like (they can’t); and, even crazier, that local sheriffs ought to arrest federal officials implementing the Affordable Care Act, which is quite literally a call for insurrection against the federal government. I guess those are just colorful ideas.

National observers also didn’t find it disqualifying when Tom Cotton, who is favored to become the next U.S. senator from Arkansas, expressed his belief that ISIS is now working with Mexican drug cartels to infiltrate America over our southern border.

Why do candidates like Cotton and Ernst get away with stuff like that, while Grimes gets raked over the coals for not wanting to reveal her vote and someone like Todd Akin can lose a race over his ruminations on “legitimate rape”? It’s because the standard being employed isn’t “Does this statement reveal something genuinely disturbing about this candidate?” but rather, “Is this going to be politically damaging?” Grimes’ chief area of political vulnerability is that she’s a Democrat in Kentucky, where Barack Obama’s approval ratings are low, so whenever the question of Obama comes up, reporters are watching closely to see how deftly she handles it; if she stumbles, they pounce. Akin got hammered for “legitimate rape” not so much because of how bogus and vile the idea is, but because reporters knew it could have serious consequences among women voters, given both the GOP’s constant struggles with women and the fact that Akin’s opponent was a woman.

Of course, these judgments by reporters end up being self-fulfilling prophecies: if they decide that a “gaffe” is going to have serious political effects, they give it lots of attention, which creates serious political effects.

And in the last few years, there’s a baseline of crazy from the right that the press has simply come to expect and accept, so the latest conspiracy theorizing or far-out idea from a candidate no longer strikes them as exceptional. Sure, there are exceptions: For instance, Republicans Sharron Angle and Christine O’Donnell both saw their candidacies derailed by their crazy or outsized statements. But their utterances were truly, deeply bizarre or comical, so they broke through.

But during this cycle, Republican crazy just hasn’t broken through at all. It’s almost as if the national press has just come to accept as normal the degree to which the GOP has moved dramatically to the right. At this point so many prominent Republicans have said insane things that after a while they go by with barely a notice. This is an era when a prominent Republican governor who wants to be president can muse about the possibility that his state might secede from the union, when the most popular radio host in the country suggests that liberals like Barack Obama want Ebola to come to America to punish us for slavery, and when the President of the United States had to show his birth certificate to prove that he isn’t a foreigner.

So ideological extremism and insane conspiracy theories from the right have been normalized. Which means that when another Republican candidate says something deranged, as long as it doesn’t offend a key swing constituency, reporters don’t think it’s disqualifying. And so it isn’t.