That's a good point. Left the way things currently are going, the ayatollahs are bound to fall within a year or two. But perhaps they think that if they can somehow provoke us enough to get us to engage them militarily (and possibly stretch our forces too thin), that would throw a measure of unpredictability into the situation that would be favorable to them. .....banking on a regional "holy" war. Either way they must know they're screwed, so why not provoke war and see what happens?