Unless you spend half your time in Bermuda, you know that Michael Bloomberg’s poll numbers are down. Way down. His approval rating citywide now stands at 48 percent; in Brooklyn, it’s sunk to 29 percent. Even in his Staten Island Republican stronghold, it’s dipped below half.

Pundits blame the dive on resentment over the mayor’s wealth. Or the Bermuda weekend. Or the smoking ban. But it’s something else entirely: Call it the Hopkins effect.

Bloomberg is a graduate and former chairman of Johns Hopkins University (electrical engineering, ’64), and alumni of the Baltimore school will recognize a strikingly familiar personality at work. (Full disclosure: I’m also a graduate.) Hopkins has a knack for producing a singular sort of character—one in which the DNA of the computer jock has been gene-spliced with that of the arrogant med student—and it’s an ugly hybrid. The classic Hopkins grad isn’t just a dork; he’s a dork with a superiority complex. No less a figure than Steven Muller, a longtime president of the university, once remarked upon the school’s “nerdlike atmosphere” in a speech, and virtually every Hopkins grad can reel off a list of classmates who fit the mold. “Pools of extreme intelligence together with pools of total cluelessness,” says one alumna. “I probably knew half a dozen Michael Bloombergs there,” says another graduate. “And I stayed away from them.”

“Hopkins is results-driven,” says alumnus Dan Holzer—gather data, solve the problem. “Bloomberg will pass a property-tax hike of 18 percent, and it doesn’t matter to him that it’s going to make a lot of people unhappy.” He’ll pass the smoking ban because it’s good for you. If you disagree—well, clearly, you’ve just proven yourself too stupid for your opinion to count! Consider the joy Bloomberg took last week in touting the success of his midtown-traffic-rerouting program. Cars now roar along at 6.1 miles per hour rather than 4, the mayor proclaimed, adding, “It would appear that it was a very good idea.” He’s the Republican Al Gore.

How’d this guy get to be mayor in the first place? Blame the Hopkins Effect again. In the period after 9/11, New Yorkers thought they had better put someone in charge who knows things. But a year and a half later, with the economy still stalled and terror fears still all too present, New Yorkers seem to have turned on the good student. Maybe we’d do better with a cheerleader.