I am hoping there is a factual, definitive answer to this.
According to the Presidential Succession Act of 1947, if for some reason the president is unable to carry out his/her duties, they are succeeded by:
1 Vice President of the United States
2 Speaker of the House of Representatives
3 President of the Senate pro tempore
4 Secretary of State
5 Secretary of the Treasury
6 Secretary of Defense
7 Attorney General
When Agnew resigned, Carl Albert temporarily was in the prime spot. That happened again when Ford became President and Rockefeller had not been confirmed.
What would happen though if something happened after election day but before the inauguration?
Let’s suppose that it is now November 5, 2008. The election was clean and fair and the Smith/Jones ticket won (I refuse to get into the partisan nastiness that could come up if I chose real candidates). Unfortunately, VP-elect Jones accidentally chokes on the olive in a celebratory martini and dies.
Normally, Nancy Pelosi would step in to fill the void, followed by Robert Byrd as the President of the Senate. But the voters decided on cleaning house and didn’t reelect the incumbents and they are out! Since those positions are chosen by the members of the House and Senate, respectively, there is a void. The Cabinet level positions are effectively empty since the positions have not been filled and confirmed by Congress.
So, in that unlikely scenario, who would be sworn in on January 20, 2009 as VP?