I just had a thought, maybe it wouldn’t apply in the case of this show with the President dead and the Tyler precedent making the Acting P the P but say the President was in a coma and the VP was dead along with the rest of the line of succession and you had the Secretary of Dog Catching as an acting President, if he appointed a new VP, would the new VP then supersede him as acting President? Would a newly elected House Speaker supercede him also?
An Acting President (i.e., a person acting as President during a temporary vacancy, such as would occur if (i) the president is incapacitated as per the 25th Amendment or (ii) the presidential election gets thrown into the House and none of the candidates has received the vote of 26 state delegations by January 20) may not nominate a VP pursuant to Section 2 of the 25th Amendment. Only a proper President may do so. The 25th Amendment is very clear when it uses the terms “President” and “Acting President.”
Assuming for the sake of argument that the Speaker of the House is an “Officer” eligible to be placed in the line of succession (which I do not believe is the case, irrespective of what Congress legislated at Harry Truman’s behest; similarly, James Madison, who pretty much wrote the damn Constitution, argued that the line of succession adopted by the First Congress, which included the President Pro Tempore of the Senate and the Speaker of the House (and no one else), was unconstitutional), then the new Speaker would supersede the Secretary of Dog Catching as Acting President from the moment of his election as Speaker. Of course, that would result in the paradox that Madison pointed out and that is still true today: Since the president can’t be a member of Congress pursuant to the Incompatibility Clause, then the Speaker would have to resign from Congress if he became Acting President, and since the Speaker must be a member of the House (irrespective of what some armchair scholars claim—the position of Speaker was based on the Speaker of the(British) House of Commons, who had to be, and always has been, a Member of Parliament), then such person would no longer hold the position (Speaker of the House) that allowed him to be Acting President in the first place. That is one (structural) reason why the Constitution should be interpreted to permit only Executive Branch officers from being in the line of succession. (There also is a textual reason why a legislative officer should not be permitted to be in the line of succession: Throughout Article II, which is where the line-of-succession clause is located, the term “Officer” refers to an “Officer of the United States,” a term that includes Executive Branch officers and Article III judges but not members of Congress.) So if the Constitution still means something, neither the Speaker of the House nor the President Pro Tem could act as President of the United States.
Fortunately, an Acting President may nominate a new Secretary of State, who, upon confirmation by the Senate, would become the new Acting President until the President woke up from his coma.