If the definition of insanity is doing the same thing over and over expecting different results, then Republicans lost their minds chasing the Clintons down rabbit holes years ago.

They spent the 1990s turning every gnat fart in the Clinton White House into a six-part inquiry, and at the end of it, Bill left office historically popular. They’ve spent the better part of the 2010s doing the same thing to Hillary, and though she is emphatically not historically popular, Republicans have, in the process, tended to humiliate themselves and abet Donald Trump—the one person politically incorrect enough to call her crooked and accuse her of playing the woman card, at last, at last.

What we witnessed Thursday was part of a pattern that goes back more than 20 years. A Clinton does something—in some cases innocuous, in this case worthy of criticism—and her political nemeses respond completely out of proportion. They’ve invested so heavily in the fantasy that Hillary’s one email or utterance away from complete self-destruction that they can’t bring themselves to accept anything less than the highest return. A sunk cost fallacy of power politics and partisan score-settling.

The pattern has become familiar enough that reporters now anticipate it. When FBI Director James Comey excoriated Clinton for her sloppy email protocol, it was almost a foregone conclusion that Republicans would peer so deeply into the mouth of the gift horse he’d just given them that they’d pop out the other end. On Thursday, they hauled him up to Capitol Hill knowing that any number of right-wing members on the House Oversight Committee might attack his integrity, and sure enough they did. Now the chase continues.

What made this episode unique is that the same media that expected Republicans to overreach played a critical role in increasing their expectations of a political windfall.

Republicans in Congress and their conservative media allies largely brought this upon themselves. They were the ones who made right-wing sop out of baseless speculation that Clinton might be indicted for violating a law nobody’s ever been convicted of violating.

But due to a strange brew of incentives that proved toxic—the competition for eyeballs, the lack of subject matter expertise, the industry standard of reportorial balance—the mainstream media did nothing to puncture this myth. To the contrary, it treated the threat of indictment as a permanent question mark hovering over Clinton’s campaign like a dark cloud. In a different media ecosystem, this wouldn’t have happened. A mix of common sense and truly basic research and reporting would have established a consensus that Republicans were trying to gin up intrigue and damaging innuendo, but that an indictment was extraordinarily unlikely. Instead, the remote odds of one came to be seen as something like a 50-50 proposition, to the point where even professional Democrats began to worry Clinton might be charged with a felony and prosecuted.

By the time Comey handed down his utterly predictable recommendation that prosecuting Clinton would not be reasonable, it had become a foregone conclusion on the right that an indictment was imminent, and could only be sidestepped through corruption.

The ensuing dissonance between what this unimpeachable, Republican FBI director had concluded and what the Republican Party had trained its voters to expect explains why some members of the oversight panel felt compelled to question Comey’s honor. It also made it impossible for Republicans to congratulate themselves on a job well done, thank Comey for laying out the truth about Clinton’s “extreme carelessness,” and use his statement as ammunition in the election.

The only other way to resolve the inconsistency was to suggest that Clinton must have lied criminally along the way—to Congress under oath, or to the FBI in an effort to obstruct justice, or both. Jason Chaffetz, the committee’s chairman, thus promised to refer Clinton to the FBI for another investigation.

This will likely produce another disappointing finding (Clinton may have presented facts in a misleading way, but there’s no reason to believe she perjured herself). It will leave the conspiracy-minded GOP base blindsided once again, and give way to some other tangentially related but probably fruitless inquisition. We will be dealing with the fallout of the email investigation well into Clinton’s first term in the White House, unless Democrats reclaim the House and Senate. But now, instead of investigating Clinton for endangering national security or for some other crime related to her public service, it will transform into a shameless witch hunt. The kind of partisan onslaught that only seems to make the Clintons more powerful. And thus the insanity begets itself.