The 107th Congress has now been sworn in, and Bill Clinton’s still the president. Dubya comes along in 17 days. All righty - my question is, why is there an overlap between the swearing-in of the two entities? Is it just a matter of timing to ensure that there’s backup for the president/v.p. if something should happen on Inauguration Day?
I believe the gap is to allow the new Congress to handle it’s tie-breaking duties in the Presidential election. The electoral votes aren’t officially counted until January 6th, and if there was a tie, the new Congress would have to choose the new President. The Twentieth Amendment gives them 2 weeks (14 days) to do that, which almost makes sense.
I believe that the overlap was built in so that the new Congress would settle any electoral college disputes instead of the old Congress.
Prior to the adoption of the 20th Amendment, there was no overlap. Jefferson and Adams were both chosen as president by a lame duck House.