I'm happy that Rex Tillerson is a moderating voice.  "Fourth in line" is not Secretary Tillerson.  In elementary school we learned that the President pro tempere is the 4th in line after the speaker of the house- after the vice-president in a real catastrophe.  So it would be Pence, Ryan and Hatch, then Tillerson. 
Heather Nauret(?) should develop a longer fuse in the press room, comes off very snarky compared to past State Department spokesmen. Studying a little history wouldn't be a bad idea either. Remember the mistake Alexander Haig made?  Maybe not! Why does no one know these things about our government any longer? To serve in the cabinet or in any branch of our government-this should be a requirement.