Stockard Channing really did break her ankle in real life (it was a hiking accident). Rather than shelving the character or severely limiting where she could be shown, it was decided to give the First Lady the same injury in the show.
The Assistant Secretary of State, played by Hal Holbrook, refers to the U.S.S. Pueblo incident, saying, "I was there." Holbrook played the captain of the Pueblo in Pueblo (1973).
Hal Holbrook and Martin Sheen also appeared together in the groundbreaking 1972 television movie That Certain Summer, in which they played lovers.
Albie Duncan (Hal Holbrook) begins his recitation of similar incidents by citing the 1968 boarding and capture of USS Pueblo (AGER-2) by North Korea.
The submarine reports its position as 36.6 degrees north, 110 degrees west - that's in Arizona, hardly off the North Korean coast.