The one metric on which Senator Clinton did not have to resort to Enron accounting in order to count herself ahead, superdelegates, has finally fallen, as Sen. Obama has picked up enough superdelegates to be ahead in that category as well. The Grey Lady piece cited notes that Sen. Clinton "regrets" making her remarks about she being stronger among less-educated White voters.
The cynical among us would say she regrets it because it didn't work, and only accelerated a pre-existing trend among super-delegates to bolt for Obama. I will give her the benefit of the doubt, and say that in her exhaustion and frustration, she simply forgot that the point of dog-whistle code words like "blue-collar" and "small town" is to at least have the cover of arguing that you were not "going racial"... cover lost when actually "going racial" and using words like "hard-working White Americans." In other words, a simple gaffe, like Obama's use of the term "bitter" (and clinging to religion and guns) to describe rural Pennsylvania voters. [The Onion, as always, has the lowdown on this.] But the trend was inevitable anyway, as the real metric-- delegates selected by the voters, is pretty much locked in with Obama having an insurmountable and not insignificant lead.
And there we have it: the rationales for the continuation of Sen. Clinton's campaign continue to erode rapidly, as Obama continues to edge closer to clinching the nomination, just as Sen. Clinton's uphill battle faces even steeper odds as some of her own supporters among superdelegates are bolting to Obama, while none of his defect to her.
At some point, someone will have to honestly ask if the net gain of increased coverage of Democrats caused by the continuing horse-race (appropriate that the horse-race travels through Kentucky soon) is offset by internal divisiveness, and getting White Democratic voters used to voting against their nominee.
Time will tell. For the moment, the tone of the race may be less rancorous for a while, and Team Obama prepares for the general.