Among the many South Park regulars and guest stars that appear on the final stage are: Big Gay Al, Sally Struthers, Cheech and Chong, Vishnu, the Grim Reaper, Starvin' Marvin, a Jakovasaurs and a Visitor.
The concluding message of this episode (that the key to America is the balance between pro-war conservatives and anti-war liberals) ended up being the main idea behind Parker and Stone's movie Team America, released the following year.
South Park's 100th episode, though some consider the 100th being Cancelled (2003) if you count the two Christmas cards and South Park: Bigger, Longer & Uncut (1999).
The episode's message is first summed up by Benjamin Franklin, voiced by Norman Lear. Ironically, Lear himself, being a staunch left-leaning liberal, may have disagreed with the content of his lines.