I'm writing this before the results from Ohio and Texas are known. And in an election year where events have been brutally unkind to predictions, it seems folly to pronounce Hillary Clinton a dead woman walking, but I'm going to do it anyway. After all, the great difference between pundits and coroners is that pundits don't need to wait for actual death to commence the autopsy.

Whatever the results of Gotterdammerung Tuesday are, it seems clear that Clinton won't be the Democratic nominee. Indeed, the only way for her to win is for Barack Obama to lose by his own hand. Like some invulnerable demigod who can only be destroyed by his own hubris, Obama is now mathematically and politically immune to Clinton's attacks. She is now the true candidate of hope.

That's ironic, given that Clinton's whole campaign has been based on the premise that she is the careful, strategy-obsessed candidate. From health-care policy to hairdo, Hillary is a planner. As I've said before, her idea of spontaneity is to leap from her prepared text to her prepared index cards.

Hence the glorious failure that she and her strategists neglected to imagine they'd even need a strategy after Super Tuesday.

And there were other more obvious mistakes. In the mother-of-all-change elections, the Clinton team opted to make her campaign about "experience" and about veering "back to the future," in Bill Clinton's words. Or were those Hillary's words? Is there a difference? Confusion on this point is understandable given that the ex-president not only speaks as if a vote for Hillary is a vote for him, but also seems to think that voters are actually voting for him.

The decision to use Bill as a surrogate - the ultimate Hillary in a pantsuit - has been hotly debated for months. The arguments in favor (he's popular with the base, he gets enormous media attention, he's an indefatigable campaigner) and the arguments against (he's controversial, he puts the campaign "off message," his narcissism is all-consuming, etc.) all seem to have missed the larger point. By dragooning Bill into the race - or, more accurately, by failing to prevent him from leaping into it - the Clinton team reinforced the perception that Hillary is the closest thing to an incumbent the Democrats have.

This is not the year for incumbents. This is not the year for a candidacy whose central argument amounts to "it's my turn." Continued...