It doesn’t make any sense on the surface. He could have gained PC sympathy points by extending ‘diplomacy’ out past the American election and showing pictures of dead Russians. He wants Obama to be elected President and his early move would benefit McCain. So why has he already moved?
August 2008 only makes sense if he is moving chess pieces in advance of something coming up quickly. I believe that Putin is deploying his forces in advance of an attack on Iran, which he must sense as being imminent.
He wants the option of denying oil to the West. A case of beer says that there are Spetsnaz in the Saudi sand tonight.