Back in 2004, I had environmental and political worries about nuclear energy. Low safety standards in Iran, evidenced for example in the extremely high incidences of road accidents, would make anyone nervous about the possibility of another Chernobyl occurring in Iran. Politically, I argued that possessing nuclear weapons would embolden the new government of Iran, which was already exhibiting an unimpressive record on democracy and human rights.

But the events of the past two years -- most notably with what's happening in Iraq, along with last year's presidential election and other unfortunate events in the region -- has left no doubt in my mind, and in the minds of lots of secular Iranians, that the U.S. is behaving more and more like a reckless imperial force in search of new sources of energy and new markets to expand to economically. Therefore, even if Iran becomes the most peaceful, secular and progressive, yet still independent state on the planet, the U.S. would be unable to tolerate it. The U.S. would seek new excuses to topple Iran's government and install their favorite instead.

For this reason, I believe Iran needs to produce nuclear weapons as a defensive mechanism, to deter the U.S. today and the ever-expanding and equally energy-hungry China tomorrow.

Moreover, a nuclear Pakistan has always been a threat to Iran and a source of instability. Radical Wahabi and anti-Shia groups such as Sepah-e Sahabeh have murdered Iranian citizens or diplomats in the past twenty years. They helped create the Taliban, which almost got into war in Iran in late in late 90s.

But making nuclear weapons even for totally defensive purposes is not easy now. Iran could only get away with it by stopping enrichment now, voluntarily normalizing relations with Israel and the U.S., and withdrawing from the NPT. Then it could start making the weapons -- secretly or maybe even publicly. It's only then that the world would tolerate a nuclear Iran.