I don't think we need to delve for any psychological explanation of a deep change in Bill Clinton's character, because I don't think there's been one.
After all, the tension (if it is a tension) between Clinton the smart and charismatic progressive and Clinton the brutal bare-knuckles campaigner was such a common trope coming out of the 1992 campaign that it could get put at the center of Joe Klein's Primary Colors. Clinton may have beat Bush in the fall of 1992 by feeling the audience's pain--but he beat Paul Tsongas in the spring by blanketing Florida in lies and deceptions about Social Security and Israel. Nothing Bill's done in the last several weeks should come as any surprise to anyone who remembers Florida '92. Later, he dispatched Jerry Brown with one of those strategic shows of temper, exploding at him in a debate that Brown had crossed the line by mentioning the corruption charges involving shady deals between the Arkansas state government and Hillary's law firm: "You ought to be ashamed of yourself for jumping on my wife. You're not worth being on the same platform as my wife." (Because, of course, it turned out that neither Whitewater nor Hillary had any drag effects on Bill in the future that Democratic voters in 1992 might have wanted to think about, and so both were off-limits as topics, right?)
When the first comparisons between Obama and reformist eggheads of past Democratic primaries (Tsongas, Stevenson, Paul Simon, Gary Hart) started surfacing, my thought was, "Bill Clinton's very first lesson in national politics was how to eat a candidate like that for lunch." Now, either it turns out that Obama has a cannier sense of politics than those others, or that Bill's lost his touch, because it's not working so well this time. But I have limited patience for those who are now shocked, shocked! that Bill can be a mean guy on the campaign trail.
This is to say nothing, of course, of Clinton's brutal effectiveness at crushing Republican adversaries--Newt Gingrich in roughly calendar year 1995, Ken Starr in calendar year 1998. (And throughout he was quite willing to brutalize--or to authorize his deputies like James Carville to brutalize--the names and reputations of the women involved in his various sex scandals.) I understand that most who are flocking to Obama's defense now are glad Clinton so ruthlessly crushed his GOP opponents in the 1990s. But that shouldn't blind them to the reality that he did so with no particular regard for niceties or honesty.
And yet he was an excellent President, all things considered. Sometimes in spite of himself, sometimes thanks to constraints set on him by his opposition, but still. For many, many years he's been so convinced of his own importance, his own ability to get great things done, that he's been willing to crush those who got in his way. (He was sure that he could win the presidency in '92 and make a difference, and that Tsongas couldn't; so Tsongas had to go.) And however great a moral flaw that is, he wasn't crazy to think that he could be an important and effective leader. That doesn't make him two different people. He is now, and was then, someone of political brilliance, charisma, and ruthlessness. All the same guy.
--Jacob T. Levy