As I read the news of Iran's continuing intransigence on nuclear issues, I thought of a conversation with an Iranian engineer in the Shiraz airport this past April as we waited to board a plane to Bahrain. He would go on to Germany where he had lived for many years.

This conversation was one of several experiences while in Iran this past spring that came to mind as I read calls for "crippling" sanctions in response to the news in mid-September of Iran's second and previously undisclosed nuclear enrichment site in Qom.

Sanctions against Iran have a long history. In 1995, President Bill Clinton prohibited all commercial and financial dealings with Iran. I felt the continuing consequence of this ban when I could not use credit or debit cards in my travel there.

A year later, Congress toughened the sanctions to penalize other countries that might invest in developing Iran's capacity to refine or further develop its petroleum resources. As a result, the capacity of refineries in Iran is inadequate to meet their needs for gasoline which must be imported although the country is a major exporter of petroleum.

After the election of reformist President Mohammad Khatami, President Clinton eased, but did not eliminate, sanctions. In 2001, Congress passed and President George W. Bush signed a renewal of the sanctions bill despite the pleas of President Khatami. The fact that Khatami's suspension of nuclear enrichment did not achieve an end to sanctions may have encouraged Ahmadinejad to pursue a more aggressive course when he was elected president in 2005.

Ahmadinejad immediately reversed the suspension of nuclear enrichment and, we now know, began construction of a second enrichment facility in the mountains near Qom. After this site was disclosed in September, the leaders of France, Great Britain and the U.S. stood together to announce severe sanctions if Iran does not back away from these steps which enable their development of nuclear weapons. Russia now seemed prepared to support sanctions, as they had not in the past. Chinese support remains a question.