Half-formed thought ...
In effect, Obama is already serving as President in most of the ways that matter.
Theoretically the Pres has three main tasks: head of the executive branch, head of the military, and final decider on legislation. Bush never even started to perform the first job. The executive branch has been running rogue without supervision since 2001. He did start on the second, but got bored. The military has been running without supervision from 2003 through 2006. He ignored the third as well, never vetoing bills even when he claimed to oppose them.
In short, and in direct contradiction to the standard leftist paranoia, Bush is not a tyrant but a lazy rich boy who spent 6 of his 8 years doing nothing at all.
Old common law includes the 'Doctrine of Adverse Possession',
rarely enforced now but still valid. If you own a piece of property but don't occupy it, maintain it, or use it for several years, you've effectively lost your title. A squatter who occupies and maintains the property may gain the title.
Obama is the Adverse Possessor or disseisor
. Bush has lost title to the Presidency by failing to occupy and maintain it. Obama, though in theory only the Prezlek, has already started clearing the sidewalks, planting the crops and telling young dickheads to get off the damned grass. He thus owns the office.