So the correct attitude toward U.F.O.s cannot be a simple Hofstadterian dismissiveness about the paranoia of the cranks. Instead, you have to be able to reject outlandish theories and acknowledge a pattern of government lies and secrecy around a weird, persistent, unexplained feature of human experience — which we know about in part because the U.F.O. conspiracy theorists keep banging on about their subject. The wild theories are false; even so, the secrets and mysteries are real.

Another example: The current elite anxiety about Russia’s hand in the West’s populist disturbances, which reached a particularly hysterical pitch with the pre-Mueller report collusion coverage, is a classic example of how conspiracy theories find a purchase in the supposedly sensible center — in this case, because their narrative conveniently explains a cascade of elite failures by blaming populism on Russian hackers, moneymen and bots.

And yet: Every conservative who rolls her or his eyes at the “Russia hoax” is in danger of dismissing the reality that there is a Russian plot against the West — an organized effort to use hacks, bots and rubles to sow discord in the United States and Western Europe. This effort is far weaker and less consequential than the paranoid center believes, it doesn’t involve fanciful “Trump has been a Russian asset since the ’80s” machinations … but it also isn’t something that Rachel Maddow just made up. The hysteria is overdrawn and paranoid; even so, the Russian conspiracy is real.