[Repeal 16-17]

GWB's term doesn't end on a specific date.

Yes it does. From Section 1 of the 20th Amendment:

The terms of the President and Vice President shall end at noon on the 20th day of January

[Right Wing Assault]

The terms of the President and Vice President shall end at noon on the 20th day of January

So it is possible we could be presidentless. That means the next in line would be... OH NO!