The Obama campaign made a tactical mistake in claiming that he would declare final victory tomorrow when he expects win enough pledged delegates to have a majority (but not have clinched the “magic number” to nominate, which is in dispute, and will be decided by superdelegates). In the first place, the story line is a bit muddy — “majority of pledged delegates” does not really equal victory and will be hard to define as such. Secondly, it makes him look nervous — if his victory is inevitable, why not just let things play out for a few more weeks instead of rushing it with a shakily defined claim? Third, it is a needless affront to the Clinton supporters and as such reinforces the perception that Obama is just a little bit too smug. Finally, if reports that Hillary is closing the gap in Oregon are true, Obama might wind up with two big losses tomorrow night, and that scheduled declaration that the race is over will just be hanging out there as a major embarrassment.
UPDATE: I see now that the Obama campaign is ramping back on pre-emptively declaring victory. The rationale being given states everything except the fact that they really will not have won.