Once Iran gets nuclear weapons, they may believe that they are no longer vulnerable to either.

Iran uses terrorism very instrumentally as an element of foreign policy; they are not just intent on just killing as many people as possible, like al Qaeda. There's no reason to believe that would change.

Our support for the Shah, the CIA coup in 1953 - has become infused into the Iranian political discourse. The regime that came to power in 1979 during the Iranian revolution actually defined itself as anti-American, and that's now a critical ingredient in the Iranian domestic political debate. That really is the source of our problems - the regime in Tehran continues to see itself as opposing the US. In their eyes, everything the US does is directed at them in a very malevolent way, and therefore they have to fight back against it.

The Iranians are very skilled terrorist, and we'd have to expect that they'd hit at us as hard as they could. Especially in Iraq, where they have a great deal of power and influence.

More likely, there were probably some real divisions within the Iranian government - some groups wanted to ally with al Qaeda against us, others didn't want to have anything to do with that. So I think that debate resulted in no decision being made for awhile. The problem was they left the al-Qaeda folks in Iran in the hands of their intelligence services and Revolutionary Guard, who didn't really keep an eye on them - and may not have kept an eye on them on purpose.

The real concern is that Iran would do what Pakistan did. Pakistan wanted nuclear weapons, like Iran, purely for defensive reasons - to defend itself against India. The problem was that once Pakistan acquired the weapons, it allowed the country to be more aggressive. So they stepped up their support for the Kashmiri terrorists, and it led very quickly to the Kargil crisis in 2000, which almost sparked a nuclear war between India and Pakistan.

Most Iranians are sick and tired of revolutions. They've had one for the last 25 years, and they don't want another one. Those who've tried to spark another revolution have failed time and again. I don't think there's any evidence that somehow, if the U.S. gave these guys the high sign, it would make regime change somehow more likely. Every time the U.S. has tried to interfere in Iranian affairs to help a particular group of Iranians, it's backfired on us, and hurt the group we tried to help.