This movie has a "crazy credit" that says something to the effect that: Some scenes contain dialogue that has been invented for dramatic purposes, but not the scenes you think.
In other words, this low budget movie* used research not only based on public statements but also some of the private conversations that became available via the Freedom of Information Act.
So you hear these iconic figures making statements that are somewhat cynical. They recognized the limitations of real world politics and, in some cases, their own foibles.
*Actors do not look very much like the famous persons they portray, and settings are often so obviously a hotel room rather than, say, the White House or whatever, that you can almost here the hotel manager banging on the door and yelling, "Check time was 11 a.m.!"