Character mistake: In the 11/14/2005 US Army Rangers report about Peter MacLeish, the word captain right under MacLeish's signature is misspelled "captian."
Character mistake: The ‘Brit', Damien from Scotland Yard, and Emily are outside the archive facility - Damien pronounces ‘route' the American way (rowt, rather than root).
Character mistake: President Kirkman calls a soldier a Corporal when she's wearing the rank of Specialist. Next, he calls a soldier Private when he is also wearing the rank of Specialist. (00:04:46)
Character mistake: The chessboard on the desk part way into the episode is set up wrong. Any chess player knows the "white on right" mantra for the white square being in the right corner of the board. In the show the entire board is off and black is in the lower right corner. (00:11:20)
Answer: The line of succession is VP, Speaker, President Pro Tempore, then the Cabinet Secretaries in the order the department was created. If none is qualified, then the Chief Justice or senior member if no Chief or Chief is ineligible or declines, acts as POTUS until either the House chooses a new Speaker or the Senate chooses a new Pro Tempore, whichever is first.