Say there’s a mass disaster or terrorist attack in Washington. Tragically, the President, Vice President, Speaker of the House, President pro tem of the Senate and all but one member of the Cabinet are killed. The Senate is either in recess at the time or is itself wiped out entirely. The sole surviving Cabinet secretary becomes President. The next day, she makes a recess appointment of a trusted politico as Secretary of State.
A week later, stressed out by her job, the President has a fatal heart attack. Would the new Secretary of State become President?
The Presidential Succession Act of 1947 makes no mention of recess appointments. Whoever is legally in the line of succession on the day it is invoked becomes the President (or acting President in some cases) and is in that office until the end of the that presidential term. I don’t think the fact that they were recess appointments and would expire before the end of the presidential term matters. Once they become president their previous status is irreverent.
But by then Congress may have appointed a new Speaker of the House or president Pro Tempore of the Senate and the point would be moot. As long as there was one surviving member of each house that would happen. I can’t imagine them staying out of session during this crisis.
But change the scenario so that the only survivor in the line of succession is a recess appointment and the same question holds. Once congress is back in session it shouldn’t change the fact that we have a President and the path they took to the office is not relevant.
But it would probably take a Supreme Court decision to settle the matter.
Subsection (d) of the Presidential Succession Act is the part that sets forth that the cabinet officers succeed to the Presidency after the VP, Speaker and President Pro Tempore.
Subsection (e) provides in relevant part:
In other words, under Subsection (e), officers appointed under recess appointments (who were not subsequently confirmed by the Senate) are not eligible to succeed to the Presidency under the Presidential Succession Act.