“In government, people are more willing to sacrifice egos to do something right from the efficiency standpoint,” one friend says. In the world of academic administration, where egos play a greater role, Summers will have to watch himself. “Someone will give a longwinded response, he’ll cut them off. That will hurt him.”

And though friends practically say they will take a bullet for Summers, they say he’s not always the most relaxing person to talk to—his mind always active, his debater’s instincts always there. “When you’re in a conversation, this could get very exhausting and sometimes frustrating,” another friend says.

The comparison with Rubin is revealing: “Rubin was just a mellow guy, you’d feel relaxed talking to him. Very few people truly felt relaxed talking with Larry.”

Rubin argues that these perceptions are flawed and that neither impatience nor arrogance are likely to pose a problem. “He’s very good at sitting down and discussing the ins and outs of an issue for hours when the issue warrants long discussion,” Rubin says. Equally importantly, Rubin says, “He got to be able to sit there—sometimes on Capitol Hill—even when the merits [of the discussion] would not warrant prolonged engagement. He was very diplomatic.”

And on the flip side, some think that a leader needs to be impatient to be effective.

“I have a reputation for being brash, but you do want someone who is impatient,” Dukakis says. “Keynes said that in the long term everybody will be dead—you don’t want to sit around and do nothing.”