The current presidential-succession statute uses the same line of succession for every conceivable situation. But there are many different types of potential succession scenarios. Succession need not—and should not—be governed by a one-size-fits-all approach.
Before the Twentieth Amendment was ratified in 1933, the Constitution authorized Congress to provide only for double vacancies during the term, when there already is a President and Vice President. Recognizing this gap, Section 3 of the Twentieth Amendment empowered Congress to cover inauguration-day double vacancies: at the outset of a term, when nobody is available to become President or Vice President in the first place.
Significantly, Section 3 gives Congress much more flexibility for inauguration-day double vacancies than Article II allows for middle-of-the-term ones. But Congress has never fully embraced its Section 3 powers: When Congress wrote the current succession law in 1947, it chose a monolithic system that ignored the distinctive needs of inauguration-day succession and left Section 3’s flexibility unused. The time for Congress to make full use of its Section 3 powers is long overdue. Moreover, Section 3 has been largely neglected by scholars. The time for a full-length published treatment of Section 3 is overdue as well.