ABC News’ Jonathan Karl ( @jonkarl) reports:

Today’s New York Times story on Herman Cain is based largely on anonymous quotes from disgruntled former staffers, but it includes an intriguing reference to a staff memo directing those traveling in a car with Mr. Cain, “Do not speak to him unless you are spoken to.”

Could the affable Mr. Cain really have a “don’t-talk-to-me-unless-I-talk-to-you” policy?

Yes.  He does.  Really.

A top aide to Mr. Cain explains to me why.

“It’s the same policy for any Secretary of Defense or four-star general,” a senior Cain staffer explained to ABC News.  “You don’t talk to them unless they talk to you, generally.  Sometimes you get guests in the car and they want to talk and talk and talk, and then Mr. Cain wants to prepare for the next interview or the next speech. and he’s very engaging, so it can be a distraction.  After a while, he gets to the point where he doesn’t want to talk, but wants to prepare for what he’s doing next.”