Q: Professor Goldstein, we are now nearing the end of what, as best we can tell, has been an exhaustive vice-presidential search process by Barack Obama. Weeks of checking and vetting and consulting. Has the process of picking a running mate always been this exhaustive?

Goldstein: It really hasn't. The process that we have now really began around 1976. Jimmy Carter clinched the nomination about a month before the convention, and he began sort of this sort of process. It began with a questionnaire that had about 19 questions. And now the questionnaires are in the 80s or hundreds of questions, so it really has exploded.

Q: In the past, as I understand it, it was not uncommon for the nominees to let the conventions pick their choice, right?

Goldstein: Well, the party leaders had the predominant say in the choice really up until about 1940. In 1940, Franklin Roosevelt said basically that he wouldn't run for a third term unless he had Henry Wallace as his running mate. And then the process evolved where the presidential candidate began to have a veto, or really, the defining say as to who would be his running mate.

Q: I think the last time -- was 1956 the last time that the nominee threw it to the convention, when Adlai Stevenson basically allowed the Democratic convention to choose between Estes Kefauver and John F. Kennedy?

Goldstein: That's right. And when Governor Stevenson did that, it really was a surprise, and he was criticized by some; they said that that reflected the fact that he was indecisive. Hubert Humphrey, who had thought that Stevenson was going to pick him, was devastated and had fully expected Governor Stevenson to make the choice himself.

Q: So what do you think led to the switch from the relatively casual process to the more elaborate and exhaustive process? Was it George McGovern's problems in 1972 with his choices, or what prompted this greater scrutiny and longer intensive vetting before we pick the choice?

Goldstein: I think a couple of things. One was that McGovern really didn't do any vetting and had, really, a sort of a haphazard process. And then following that there was the whole Agnew episode. The other thing that happened ...

Q: The "Agnew episode," meaning Spiro Agnew having to resign after being the vice president?

Goldstein: Exactly. I mean, it was determined that he had been accepting bribes while he was governor of Maryland, and even as vice president, from contractors for the state of Maryland. And he resigned to avoid indictment.

Q: And of course the McGovern case was, his original choice was Senator Tom Eagleton, who withdrew after revelations of his mental health history.

Goldstein: Right, and Senator McGovern really had never spoken, never interviewed Senator Eagleton, never spoke to him about his health issues before selecting him. The other thing that happened was that in 1976, Carter clinched the nomination about a month before the convention. And the pattern from '76 on has been that it's been clear who the nominee would be, almost always well before the convention. So you have this period of time of a month, two months, three months, even six months, where the presidential nomination is decided and the main story then becomes, who will be the running mates? That necessarily focuses attention on the choice of the running mate.

Q: Well ...

Goldstein: It used to be that the conventions, even if there was a front-runner, it was never quite sure how the first ballot would come out.

Q: On balance, do you think you can say that the modern system produces better choices, or did the old system produce better choices?

Goldstein: Well, I think, by and large, the modern system has produced good choices. Most of the people elected have been presidential. By the same token, if you look at the people who served as vice president, say, from 1952 to 1976: Richard Nixon, Lyndon Johnson, Hubert Humphrey, Spiro Agnew, Gerald Ford, Nelson Rockefeller. With few exceptions, they were really a very talented group. You might disagree with some of them, but they really were among the leading political figures of their generation. So I think that, really, since 1952, we've had able people who've been nominated, by and large.

Q: As best we know, are the presidential nominees usually satisfied with their choices? Or sometimes do they express buyer's remorse after it's all over?

Goldstein: [laughter] Well, I think we have -- it's a mixed bag. I think that certainly Jimmy Carter thought he hit a home run with Walter Mondale. No indication that he was ever dissatisfied. And similarly, I think, with Bill Clinton and Al Gore; their relationship disintegrated towards the end but that was a very effective partnership. And I think the [George W.] Bush-[Dick] Cheney one, there has been no indication of any dissatisfaction. Richard Nixon quickly developed contempt for Spiro Agnew and certainly regretted that choice. George McGovern, of course, dropped Tom Eagleton. He later said that he had made a mistake. He'd probably made a mistake in dropping Eagleton. Nelson Rockefeller, of course, through the 25th Amendment process picked Nelson -- Gerald Ford, rather, through the 25th Amendment process picked Nelson Rockefeller, then asked him to withdraw from consideration in 1976 and later regretted having asked him to withdraw.

Q: Hmmm.

Goldstein: So it's been a mixed bag.

Q: And Dwight Eisenhower obviously expressed some ambivalence about Richard Nixon over those eight years.

Goldstein: Well, he did, and really sort of hinted to Nixon that he might want to take a different position in 1956, and Nixon didn't take the bait. I think that George Bush had some regrets about picking Dan Quayle, although Bush and Quayle really, by and large, publicly indicated a great deal of loyalty to one another.

Q: To the extent nominees and presidents have, after the fact, revealed their thinking about what went into their decision, what do we know about what were the most important factors in making this choice?

Goldstein: One of the things that's interesting about the choice is how often people change their mind during the process. I think that -- for instance, in 1976, Jimmy Carter later indicated that he had changed his mind three or four times and apparently he went from favoring Frank Church to favoring John Glenn to favoring Ed Muskie to finally picking Walter Mondale. I think that in that case, the sense that Mondale really was presidential, that he was somebody that Carter felt he could work with, was very important. There have been other instances in which the -- through the process, that it really is a very deliberate one -- and that presidential nominees change their minds as they weigh different factors. I think one of the factors is, is this person a plausible president? Is this somebody I can work with? Is this somebody who'll be loyal to me? That's something that affects some presidential candidates. To George H.W. Bush, it was very important to pick someone he thought would be loyal.

Q: Well, let me ask you about someone who raises several of those issues. Obviously, there are a lot of supporters of Hillary Rodham Clinton who want Obama to put her on the ticket. When you look back, I mean, there are obviously some examples of winning candidates picking their principal rival: John Kerry picked John Edwards, Ronald Reagan picked George H.W. Bush in 1980. But overall, how common, or rare, is it for the winner to reach out to the loser in that way?

Goldstein: It doesn't happen very often. It happens maybe about 20 percent of the time. I mean, you mentioned a couple of the instances; Ronald Reagan picked George Bush. John Kennedy picked Lyndon Johnson. But there are not many episodes; more often than not, the nominee doesn't pick his principal rival.

Q: So Hillary should keep her hopes in check this week, it sounds like, based on history, at least.

Goldstein: History would suggest that it is unlikely that she would be picked. History also suggests that the people who are the also-rans -- the people who aren't the runners-up but also compete, like, for instance, Senator [Joseph] Biden -- virtually never get picked. History would suggest -- recent history would suggest -- that governors don't get picked. We hadn't had a governor since 1968. By the same token, history would suggest that we wouldn't have a competition between an African-American and a woman for the presidential nomination.

Q: Let me ask you about another historical parallel. You know there is some long-shot outside speculation today that both Obama and John McCain might be considering running mates from the other party: Chuck Hagel for Obama, senator from Nebraska; Joe Lieberman, the independent Democratic senator from Connecticut, for McCain. Now, since the 12th Amendment separated the vote for the vice president and the president in 1804, how much experience do we have with nominees picking running mates who weren't clearly from their own party, and how has it worked out?

Goldstein: We don't have much. I mean, John Tyler really was from a different party from William Henry Harrison. When, a month into their term, Harrison died, Tyler became the first president by succession. Andrew Johnson really was from a different party from Abraham Lincoln.

Q: A Union Democrat. Right.

Goldstein: And I think that's really the last time that we've had a divided...

Q: And both of those not worked out well. Certainly the Whigs viewed John Tyler as a usurper who annexed Texas. And the Republicans, Abraham Lincoln's party, ended up impeaching Andrew Johnson. I mean, neither one of those examples would really argue, I think, very much for following that road.

Goldstein: No, I think you're absolutely right. It's interesting -- the cross-party option is one that regularly comes up. I mean, Hubert Humphrey, or people on his behalf, made an approach to Nelson Rockefeller in 1968. [John] Kerry made an approach to [John] McCain in 2004. Bill Clinton made an approach to General Colin Powell in 1992. It's one that frequently comes up. It never quite connects, at least not since 1864.

Q: Well, you see the risk, of course, in both of these examples. If the president dies, you end up with a president from the other party.

Goldstein: That's right, and I would think that the closer you come to the convention, the less likely it is that you're going to spring a cross-party pick on the party faithful.

Q: All right. Well, let me ask you the $64,000 question. When you look at all the historical patterns, are there any prospects that emerge as first among equals for Obama or McCain that look to you the most likely choices?

Goldstein: [laughter] If I give you a straight answer, you'll stop considering me as an expert. So I dare not do that. I'm really, to a great extent, stumped this time. I think they both have a difficult choice. No perfect choices on either side. Competing considerations that they both face. I'm as anxious as anybody else to see what they do.

Q: Well, as we all are. Maybe by the next time we're on the air we will know. Joel Goldstein, thanks for joining National Journal On Air.