Thinking that Iran is somehow constrained by "Realpolitik" WRT nuclear weapons is a pipe dream. When their President openly calls for the destruction of Israel, and claims the arrival of the Mahdi is immanent (in Islamic theology, this is similar the Christians proclaiming the return of Jesus Christ and the day of Judgement), the thought of nuclear weapons in the hands of people who are proclaiming the Apocalypse is more than just "scary". A military "head shot" against their nuclear facilities, government institutions and revolutionary guard is probably the best possible solution we have now, unless the Iranian population can rise up en mass and overthrow their opressors.
Lenin proclaimed "World Revolution", Hitler wrote extensively about what he planned for Europe, and Imperial Japanese policy was fairly well known in the first half of the 20th century, and surprise!, they did their best to carry out their stated intentions. Intelligence commonly looks at capabilities rather than intentions, which may be one of the traps we have fallen into, in any "rational" universe, Iran is completely unable to carry out any of its stated intentions. Indeed Osama Bin Laden stated the reason for the 9/11 attacks was explicitly to provoke the United States into war, while not a rational act by any means, this played directly into his belief system (based on observed American behavior in the 1990s, he felt America was a "paper tiger", and he believed US interventions in Afghanistan, Iraq and so on would not only be slow, grinding and unsuccessful, but would also lead to an uprising throughout the Islamic world.)
WRT economics, there are large challenges facing the West (not just the United States), but adversary often unleashes creative solutions and allows merit to come forward when the status quo fails. Statist solutions to the economic problems haven't worked, but given the limited challenges we have faced so far, the system has been able to continue to function. Place a large shock and innovative solutions like President Bush's proposed reworking of Social Security or the privatization of Canada's health care system become not only desirable but absolutely necessary.
For those people who are arguing the primacy of Asian or other non-European/Western cultures, just read your history. The Chinese invented paper currency, gunpowder, sailed huge armadas in the Indian Ocean and so on, but who actually took over the world? These other cultures are internally focused, and while this gives them a certain longevity and internal stability, this does not tranlate into their long term advantage. One might ask why these Chinese fleets did not establish colonies in India, the Arabian Peninsula, the east coast of Africa, or Indonesia, when there is unambiguous evidence they had actually visited these places?