I've dismissed these allegations because, in my mind, if Hillary is seen as fatally damaging the Obama candidacy in 2008 then she will be damaged goods in the Democratic Party and will not have a shot at the 2012 nomination.
Matthew Yglesias points us to data that demonstrates that Clinton's continued campaigning is not damaging her image that much within the Party.
Whatever her subjective intentions, her past month of campaigning has succeeded in harming Obama's chances in 2008 without measurably damaging the prospects for an "I Told You So" primary campaign in 2012. For a long time, I've kept believing that Clinton's desire to run again in 2012 if Obama loses in November would get her to drop out of the race in order to avoid unduly alienating people, but as we can see her decision to drag this thing out doesn't seem to have actually alienated many people thus far.
So is Hillary Clinton really taking a calculated gamble to set herself up for 2012? Presumably her campaign has internal polls showing her much the same thing that Yglesias has highlighted here. It certainly seems possible and if you had asked me this question as recently as yesterday I would have scoffed at the notion.