Before Lee Harvey Oswald became an indelible part of one of the darkest days in American history, he was someone whom the FBI not only didn't view as a threat -- but perceived as, well, a joke. At least that's the claim of "Killing Kennedy," the new Nat Geo movie (airs. Sun. Nov. 10 at 8:00 p.m.) about the assassination of President John F. Kennedy.

In this exclusive clip, get inside Oswald's state of mind before he allegedly (as some will point out, he never went to trial) pulled the trigger. What you may not know about Oswald from your American history classes (but will see in this movie) could surprise you, such as Oswald's flip-flop between Russia and the U.S., his thwarted attempt to kill Richard Nixon (a plan vetoed by his wife Marina) and the close call after he shot at -- and narrowly missed -- General Edwin Anderson Walker.

Another surprise may be the performance of Will Rothhaar as Oswald. An actor that some may remember from bit parts on "CSI: Miami" or from the 2003 film "Kart Racer" (or not), his Oswald perfectly captures the anger and frustration of a man who dreamt of being in the spotlight -- no matter what it took. While Rob Lowe will likely (and deservedly) win kudos for his portrayal of JFK, we've known for a long time that he can nail an accent without resorting to mimicry. The news is that the little-known Rothhaar is one to watch. 

Will you be watching "Killing Kennedy" on Sunday?