But that has not stopped his colleagues from throwing his hat into the hypothetical ring. “Yes, he should run again!” said Senator-elect Jeff Flake of Arizona, flashing a smile. “I’m not saying that’s why I would support John Kerry’s nomination, but we always want more Republicans around here.” Ms. Murkowski said she, too, would like to see Mr. Brown run again. Ms. Collins campaigned heavily for Mr. Brown in his failed re-election bid, and was crushed by his loss.

The situation has become a bit awkward for Mr. Kerry, who cannot be seen as lending anything but support for Ms. Rice even though his desire for the diplomatic job is well known. Mr. Kerry has made a steady practice of dodging reporters all week, taking secret byways from the Senate floor and attending meetings to avoid the inevitable questions, and focusing deeply on a defense bill that is winding its way through the floor.

In a twist that only the byzantine politics of the Senate could produce, Mr. Kerry appears to have more unqualified support from Republicans than his own partymates, many of whom believe that Ms. Rice has been treated unfairly and may prefer to see her sent for confirmation hearings almost as an act of defiance.

“I think people around here have mixed feelings,” said Senator Kent Conrad of North Dakota. “There is a great respect and admiration for John. There is a deep loyalty to John. But I also think there is a feeling that Susan Rice has been unfairly treated.” What is more, he said, “People obviously don’t want to lose John’s seat.”

But while Democrats fear Mr. Brown in a year without Mr. Obama on the ticket, Republicans say their roasting of Ms. Rice is not a plot to bolster their departing colleague. They say Mr. Kerry has won their respect and that it is his foreign policy chops that give him an edge with them.

“He knows the issues,” said Senator John Barrasso, Republican of Wyoming, who sits on the Foreign Relations Committee, which Mr. Kerry leads. “He knows people around the world, and as we say in Wyoming, he won’t be buffaloed. I would support him.”

Mr. Kerry has worked on a variety of issues over the years with colleagues on both sides of the aisle. Even his sometimes foe Mr. McCain was his partner in the early 1990s, serving together on a committee charged with the delicate task of investigating the fates of the last prisoners of war.