Why worry about worst-case scenarios where Iran unleashes missiles and worldwide terrorism, when the best possible outcome of attacking Iran would be a failed state? Suppose the government collapses as Michael Ledeen et al seem to want. Then what?

Just what we and the world need, another Iraq. OK, it’s not a Yugoslavia, but is somewhat multi-ethnic. Here’s the bad news---if it is instead a coherent society, that just means everyone will hate us, not merely most Iranians. When even your best case is so unappealing, it might occur to you that Iran is not a nail looking for a hammer.

One SF story I read had some kind of nasty predator, on the vastly future Earth, and the locals called it a Snark. The point was if one predator goes extinct, the successor to fill the niche will be a serious badass. It might be better to keep it filled with a more tractable beast. We don’t like Allende, so we get Pinochet. We don’t like Abel Qasim in Iraq, so we get Saddam. We don’t like Mossadeq in Iran, so we get the Shah, which yields Khomeini.

Topping the list of "Be careful what you wish for" is the collapse of the Soviet Union. Beyond its very mixed results for the population is the worry about it as the most likely source of a loose nuke. So we have gone from worrying about nuclear annihilation from Russian nukes to worrying about nuclear annihilation from Russian nukes.

Bernard Brodie was an early strategic analyst, eventually at RAND, and his book "The Absolute Weapon" was the first to suggest that our military, which had previously been looked to for winning wars, now had to serve to prevent war at all costs. This frustration led to all the war gaming, counterforce strategies, civil-defense planning, missile-defense ideas, and proxy wars since WW II. It was just not acceptable that our military and its weapons could not be used. This gave us Vietnam. Brodie lost faith with the strategizing, and eventually decided his first instinct was right.

The route to security, Brodie came to feel, was in stabilizing, not destabilizing governments.