Military historian John Keegan, writing in the Daily Telegraph:
Saddam merely pretended to have weapons of mass destruction, largely to feed his own fantasies of power. Iran is actually turning itself into a nuclear weapons state, a fact disputed by none of the players on the international scene. Iran, moreover, does not seek such weapons for psychological reasons. It wants them for practical purposes, including, according to a statement by its new president, Mahmoud Ahmadinejad, a former revolutionary guard, to "wipe Israel from the map". Islamic extremists are, of course, given to blood-curdling rhetoric. Nevertheless, Iran's record must cause not only the West but all Iran's neighbours to take the threat seriously. . . .
[I]f the West is considering military action [against Iran], so are the ayatollahs. They are the sponsors of much of the insurgency in Iraq and suppliers of the insurgents' weapons. They also have intimate links with most of the world's worst terrorist organizations, including al-Qaeda and Hezbollah. Iranians may well be the missing link for which MI5 is searching behind the July 7 bombings in London. Moreover, while Iran has its own armory of medium-range missiles suitable for nuclear delivery, the ayatollahs are also known to favor the placing of nuclear warheads in target cities by terrorists traveling by car or public transport.
The whole this is worth reading. Warning: it will not make your day.