In particular, the Heisenberg Uncertainty Principle is much referred to:
The Heisenberg uncertainty principle states that locating a particle in a small region of space makes the momentum of the particle uncertain; and conversely, that measuring the momentum of a particle precisely makes the position uncertain.
The level of uncertainty is very small, hence this only becomes a significant issue when dealing with objects of incredibly small substance. Apparently, Obama's political views qualify.
So the Obama Uncertainty Principle is that - while we may fret that McCain's view will change over months or years - we cannot with any certainty state what Obama's political position is right now.
A peculiar corollary is that the more you listen to Obama, the less you know about what his actual position is.
He is some perfect paradox of complete opacity and utter invisibility.
Carl at No Oil For Pacifists has done a good job of documenting this effect regarding racial preferences. (Note that I disagree with Carl about lots of stuff. But he's nailed this one. And you find good stuff at his site regarding "Global Warming", among other things.) And I've made my own complaints previously here and here.