Aides say Mr. Biden and Mr. Obama sometimes rib each other in private meetings, and they maintain that Mr. Obama was not unduly angry at Mr. Biden for his gaffe predicting that Mr. Obama would be tested by a world crisis in his first six months in office.

Since then, however, Mr. Biden has not had much to say to the news media. Through a spokeswoman, he declined to be interviewed for this article, itself a break from his voluble past.

Obama: “Oh, Joe, you kidder, you… (aside, to aide) Don’t let him ever speak to anybody ever again.“