[Rainbow Six]

Some of them are covered in Howling Wilderness.

The Vice President (Deanna Pemberton?) stays in the White House and gets killed when Washington DC is nuked. Probably a fair chance the White House Chief of Staff gets it at the same time, either in the White House or on board the Kneecap aircraft.

You could probably argue that several others on that list would have been on the Kneecap as well, making the Kneecap's crash the main factor behind the years of turmoil between Milgov and Civgov - a lot of people involved in the US continuation of Government programme might have been aboard the Kneecap on the basis it was the safest place to be.

IIRC the Speaker of the House (Munson?) is skiing in California but is eventually tracked down by the Secret Service and is sworn in as President. I don't have a copy of Howling Wilderness to hand, but iirc Munson dies of natural causes (heart attack?) and his successor(s) all succumb one after the other until eventually there is no one left.

Commandant of the Coast Guard is covered in Challenge #39 (the Rifle River module). We can assume he (or she) was killed as it explicitly states that Nils Holsgirder was the senior surviving Coast Guard officer, at which point he was appointed Commandant.