“Is extremism becoming mainstream in 21st-century American politics?” said Tom Jensen at Public Policy Polling. It sure looks like it, judging by our latest national poll. A third of the country, 35 percent, either thinks that Barack Obama was born outside the U.S. (including 42 percent of Republicans) or that George W. Bush intentionally allowed 9/11 to happen (25 percent of Democrats). And “a very troubled 2 percent” buys into “both conspiracy theories.”

It’s bad enough that only 59 percent of voters think Obama was born in the U.S., said Eric Kleefeld in Talking Points Memo, but 14 percent of Democrats say they think Bush is the Antichrist, and 19 percent of Republicans think the same of Obama. As PPP’s Jensen notes, it’s “strange times in American politics.”

The 9/11 “truthers” and Obama “birthers” may be new phenomena, said Arthur Goldwag in the Chicago Tribune, but what historian Richard Hofstadter called “the paranoid style in American politics” is not. The John Birch Society called Eisenhower a “dedicated agent of the communist conspiracy,” while Bill Clinton was said to be selling drugs and “bumping off” enemies. Still, that doesn’t make today’s delusional “conspiracism” any less “mind-boggling.”

It’s true that “the ‘paranoid’ style did not return suddenly this summer,” said David Greenberg in Slate, but we also can’t understand today’s “birthers and town hall screamers and Glenn Beck acolytes” by using Hofstadter’s “Goldwater-era” treatise on “right-wing fringe politics.” But Hofstadter is useful is when he talks about the history of paranoid politics—viewing past fringe movements makes today’s “more comprehensible and perhaps less fearsome.”