Since August 2011, the overall disapproval rating of Congress has hovered somewhere between 9 and 18 percent—the worst numbers ever and numbingly consistent. Everyone who pays attention to politics has known there was something going on that suggested there would be some kind of “fire next time.” You can’t have a public this disgusted without there being some kind of explosion.

But the general political response has been relatively static. Incumbents weren’t booted out in the 2012 election the way some people expected they might be, and in the run-up to 2012 only one significant longtimer (Sen. Richard Lugar) was ousted from his comfortable perch.

“The fire next time” isn’t ever really conceivable until it arrives. Maybe it arrived yesterday in Virginia’s seventh district.

It was a local election and therefore one should be careful about extrapolation. But we have an unprecedented result (the first primary ousting of a House majority leader since the post was established in 1899). We also had a candidate in Eric Cantor who, despite all the talk about his evil embrace of “amnesty,” was at crucial moments a champion of the approach of the House’s most conservative wing—and therefore not exactly the perfect example of a politician with a target on his back. (Lugar was a relatively liberal Republican, as was Sen. Mike Castle, defeated in the 2010 Delaware primary by Christine O’Donnell.)

What Cantor was, though, was one of the faces of the Republican party in Washington. He faced a candidate whom he first ignored and then attacked in very inconsistent and incoherent ways. He was, in his own way, the perfect target for voters to express their disgust and discomfort with Congress and the way Washington is working.

It’s in the nature of potential disaster that it’s difficult to maintain vigilance when the threat is not immediately on the horizon. It was for Sen. Mitch McConnell and Sen. Lindsay Graham, both of whom knew they were in primary trouble and designed races to overcome it. Eric Cantor didn’t see it coming, and the question now is whether what happened to him is a harbinger. And not just for Republicans, but for incumbents from both parties facing even minimally plausible opponents.

So it might just be that more jaws are going to drop this year, and in November. Democrats are likely to convince themselves that the anti-Washington mood that nailed Cantor is just a Republican thing. If they do not see warning signs here, they themselves might find the fire this time engulfing them as well.