The only "evidence" that Iran is pursuing nuclear weapons is mere assertion by members of the Bush administration and the neoconsevative press. Iran says it is not pursuing nuclear weapons, and the International Atomic Energy Agency inspectors say there is no evidence of a weapons program.
Iran is a signatory to the nuclear non-proliferation treaty. Under the treaty, signatories have the right to develop nuclear energy. All they are required to do is to make reports to the IAEA and keep their facilities open to inspection. Iran complies with these requirements.
There is no Iranian "defiance." When news media report "defiance," they purvey disinformation. The "seals" on Iranian facilities were placed there voluntarily by the Iranians while they attempted to resolve the false charges brought by the Bush administration. The "Iran crisis" is entirely the product of the Bush administration's determination to deprive Iran of its rights as a signatory of the non-proliferation treaty. It is just another demonstration of President Bush's opinion that his word overrules fact, law and international treaties.
Despite the clear and unambiguous facts, the Fox/Opinion Dynamics poll reports that 60% of Republicans, 41% of Independents, and 36% of Democrats support using air strikes and ground troops against Iran in order to prevent Iran from developing nuclear weapons. This poll indicates an appalling extent of ignorance and misinformation among the American public.
Sure, why wouldn't they 'fall' for the same con twice? It's even more convincing for being familiar...like television. Indeed a widespread American assumption is that only things that happen repeatedly and predictably are strictly possible. A perfectly normal, intelligent commentor at Lenin's Tomb not long ago argued that the Katrina Kaper couldn't have been planned because no agent of ethnic cleansing had ever used a 'natural disaster' for these precise purposes before. What is not familiar is impossible (for being, that is, foreign to the television genre in which the Katrina Show was broadcast. Something unknown to the formula in which spectacular history takes place).
One doesn't really believe Iran is building nuclear weapons; it's just a story (and "true" - worthy of disbelief suspension - because familiar and generic). It's not entirely clear that tens of millions of Americans really believe Iran even exists. One is simply peforming a rôle; one knows how to respond, how to play audience, whom to root for, how to answer the pollster's questions.