Research suggests that the echo chamber effect is disproportionately a problem on the right, leading inhabitants to perceive a warped reality. Many Republicans were shocked that Mitt Romney was defeated last fall because they had been assured that he would win. And a Pew survey last year found that the proportion of conservative Republicans who believe Obama is a Muslim has doubled since 2008 to 34 percent.

Then there was the time Glenn Beck aired the theory that Obama is the anti-Christ (he later said he had been joking).

The right-wing bubble makes it harder to elect Republican presidents by enforcing an ideological purity in primaries that weakens candidates in general elections. Too much time in the bubble also leaves some Republican politicians saying things that just sound nutty to independents. For example, some Republican members of the House are taking seriously the conspiracy notion that the government is buying up bullets so that private gunowners won’t be able to defend themselves.

Yet when Don Cruz of La Mancha and other extremists threaten a cataclysm that could damage the national economy, we have not just self-inflicted harm but a threat to the national well-being.