Obama is rolling and HRC is blowing steam. McCain has the nod from Romney, and it's only a matter of time before Huckabee negotiates the Veep for his social covservative shore up. This means the real story is no longer the lack of a decent Republican candidate (let's be honest, McCain is the candidate Republicans deserve, and he really isn't that bad) but the looming tete a tete between Obama and Clinton.
If Obama wins even one of the next major primaries, Wisconsin, Texas or Ohio, he will have an almost insurmountable lead. If Clinton wins all three, both her and Obama will be completely neck and neck. So what the DNC wants to make sure, no matter how the campaigns play out, is that a credentials debate does not occur. Credentials are arguably the Demcrats weakest link this election, with McCain having more political experience in sheer years than both Clinton and Obama combined. Even with Obama's ability to increase voter turnout, all his positives could be for naught if he can't explain to Democrats themselves why they should elect an unknown quantity over an established party leader.