We need some digs on the 1947 presidential succession act
Is it constitutional?
>there is a powerful (though not airtight) argument that the Succession Act’s placement of the speaker in the line of presidential succession (and after her, the president pro tempore of the Senate) is contrary to the Constitution’s Succession Clause. That clause states that only an “Officer” may succeed and act as president. Most of the pertinent commentary maintains that the term “Officer” here does not include members of Congress. If that is right, Pelosi could not constitutionally “act as President,” even though the statute says she can.
https://www.lawfareblog.com/presidential-succession-nightmare