30 years is not a long time, the USA are not afraid to get their hands dirty. I still cant see them attacking Iran though.
You also need to take into account leadership.They are when they know they know they are not dealing with a Tin Pot outfit. US is like the typical playground bully at school, happy to whip the small boys ass but when a bigger boy / nutcase boy comes along he runs home to his mummy crying like a fag.