There is also the use of lots of real people to bolster the idea that it’s real, or could be real. Some are identified (senators and other celebrities from the era) so if you don’t recognize them you should at least trust that these people are not actors.
But there are a number (like 20 or 30) of other “real” people playing themselves, including Oliver Stone. In case you don’t know him, Stone is being interviewed on Larry King Live (with the real Larry King) and he says that they’ve studied photos of the “new” president and that it’s a conspiracy. This is really one of the many little hilarious lines because Stone, of course, is famous for hatching or nurturing conspiracy theories for his movies. His “JFK” came out just two years earlier.
The other fun one most people will miss (and this dates me) is running into an unidentified Tip O’Neill on the streets. He was the real speaker of the house, and it’s a great little three seconds. He dies the following year.
Okay, the movie isn’t brilliant. But it never gets stale, and it’s well made enough to survive even a curmudgeon without popcorn. It’ll make you laugh.