In order of merit:
1.JFK (1991) ***1/2
2.Platoon (1986) ***1/2
3.Born on the Fourth of July (1989) ***1/2
4.Nixon (1995) ***1/2
5.The Doors (1991) ***
6.Alexander (2004) **1/2
7.Natural Born Killers (1994) **
I've missed out on quite a few of his films, but then I can't say...