http://news.yahoo.com/s/ap/20080430/ap_on_go_ca_st_pe/gates_iran
I suppose the best way to change the regime officially and respectively, is to first contain it, and then threaten it with gun boat diplomacy.
Normally that pisses off the liberals all over the world; starting from India, who are naturally anti-US, indirectly benefits the Seyyeds.
And that's been the story all along since the Seyyed take over. And that is why the oil price has gone through the roof and Exxon makes 1 billion a day.
Put all that together and you can see why they would rather not have a peaceful non violent regime change.