The main consideration is whether the people of Iran want such a form of government. Most polling indicates that the population could accept the form, if the substance were different -- they want a stronger economy, more freedom of movement and thought, and more interaction with the rest of the world. Half of them being under 25 years of age makes them as eager to join the workforce, surf the web and study abroad as people in other countries of the region.
More interaction with the rest of the planet is the best way to ensure that change -- evolutionary, rather than revolutionary -- takes place. Current sanctions make that harder, rather than easier.
We should put our basic values front-and-center, instead of projecting an image of ruthless, imperial domination.
The NPT should be strengthened -- or, rather, implemented in a serious way. The purpose and the letter of the pact was always that "nuclear" countries would disarm (hasn't happened), and other countries would be helped to use nuclear technologies for peaceful purposes (hasn't happened). It's time to make both parts finally come true (and a nuclear-free Middle East wouldn't be a bad idea).
On the other side of that coin, what would be the motivation for Iran to change its stance vis-a-vis the rest of the community of nations? Guarantees that it would not have to fear any more outside attempts at regime change, invasion or covert subversion would provide that motivation, many Iran experts believe.
** The day after I posted this piece, Walter Pincus, writing in the Washington Post, took note of an appearance by Israeli Defense Minister Ehud Barak on CNN (July 30). In that interview, Barak made clear that, according to Israeli intelligence, Supreme Leader Khamenei has not yet even given the order for his country's scientists and technicians to begin building a nuclear weapon. Their theory is that the Ayatollah has not done so because he assumes that the word would leak out and Israel or the United States would take action against Iran based on that directive having started the ball rolling.