From a coldly logical perspective, the last few months of Hillary Clinton's campaign approach are self-destructive at worst, puzzling at best. Doesn't she realize the damage she's causing the party by encouraging divisions like those in the Michigan-Florida flap? Does she have any idea of what this has done to her reputation, and her husband's? Do they really not care whether they help John McCain win?
I offer no psychological speculation, about the campaign or any other aspect of her life. I do have this political observation, which is consistent with John Heilemann's thorough and convincing exploration of the topic and which is based on contacts with Clinton partisans over the years.
The Clinton team doesn't worry about hurting Obama's prospects of winning in the fall, because they assess those prospects at zero. Always have. Obama might not win if he leads a bitterly divided party, but (in this view) he was never going to win. Not a chance. He would be smashed like an armadillo in the road* by the Republican campaign machine, and he would be just about as ready as the armadillo for what was coming.
When Clinton still had a plausible shot at the nomination, this assumption removed all guilt from beating up on Obama. As in: "I have a lifetime of experience that I will bring to the White House. I know Senator McCain has a lifetime of experience to bring to the White House. And Senator Obama has a speech he gave in 2002." By whittling Obama down, the Clintons were saving the party from a suicidal mistake.
And now that Hillary Clinton no longer has a plausible chance, she (and Harold Ickes etc) don't need to wake up in the middle of the night and worry: Oh no! Maybe we're paving the way for George Bush's third term! They are sure that Obama's nomination means exactly that, no matter what they do. So by definition they can't be making things worse. It is like sticking pins into a corpse -- you're not really hurting it any more. And if these efforts in fact make Obama's victory less likely -- well, then, reality will conform to their preexisting view.
If this is true, why would the campaign ever back off? Why not fight every step through the convention? Because the Clinton team is self-aware enough to understand that not everyone sees things as clearly as they do. Some deluded people might think that Obama actually had some chance of winning -- and then blame the Hillary bitter-enders when (as was always inevitable) he goes down. So sometime soon, probably after tomorrow's final primaries, it will be time to switch back to the "I am so proud to be here with Barack Obama" mode and campaign hard through the fall. Knowing, of course, how it's fated to turn out, but letting the slower students learn that the hard way.
This, at least, is what my hypothesis holds.
* Simile thanks to my years as an Austin resident.
UPDATE: I see that others have been this way before, among them John Harris and Jim Vandehei in Politico six weeks ago. This came out at a time when I was seeing nothing on The Internets, for family reasons, so I'll take it as reassuring that others have offered the same explanation, earlier.