The title refers to a variation of John Adams' reported last words in reference to his contemporary Thomas Jefferson, unaware that Jefferson had died several hours earlier. Both men died on July 4, 1826.
The actors Martin Sheen, William Devane and Steven Culp have all portrayed a Kennedy in various roles in film and television. Sheen has played both Robert Kennedy, in the made-for-TV movie The Missiles of October (1974), and President John F. Kennedy, in the miniseries Kennedy (1983). Devane portrayed JFK alongside Sheen, in The Missiles of October (1974). Meanwhile Steven Culp played Robert Kennedy in Thirteen Days (2000).
It is stated in the episode that John Adams' last words were: "Thomas Jefferson lives", when in reality it was "Thomas Jefferson survives".
H. Richard Greene plays Robert Royce, the Senate Majority Leader. However in a previous episode he played a moderate Republican Representative in the House. It is very unlikely that a moderate Republican would switch over to the Senate and be made the Majority Leader so quickly.
When Zoey (Elisabeth Moss) was kidnapped in the last season the date was May 7. We know this from the piece of paper that Charlie (Dulé Hill) had in his wallet for the champagne bottle celebration with her. During this episode she is clearly still suffering from the trauma and C.J. (Allison Janney) is covering her return as if she was found a week or two before. This would be just fine if the episode wasn't based around the Fourth of July which is a whole two months later.