The verdict is in: an Iran armed with a nuclear weapon would be disastrous for the Middle East and the world. Last month, President Barack Obama described this prospect as “profoundly destabilizing” and “extraordinarily dangerous.” The chairman of the Joint Chiefs of Staff, Admiral Michael Mullen, agreed, arguing before the Senate Foreign Relations Committee that a nuclear Iran would generate “neighbors who feel exposed, deficient and then [would] develop or buy the capability for themselves.”

This view is not new, however: the Obama administration’s rhetoric is almost identical to that of the Bush administration. Alarmists inside the U.S. government, among U.S. allies, and throughout the nonproliferation community argue that the messianic nature of the Islamic Republic and the extremely provocative rhetoric emanating from its current president, Mahmoud Ahmadinejad, make Iran’s acquisition of a nuclear capability too grave a danger to condone.

In addition, Iran has a long record of assisting terrorist groups and even using them to do its bidding — most notably Hezbollah in Lebanon — raising concerns about the support Tehran might provide such groups after acquiring a weapons capability.

A final oft-repeated worry is the possibility that Iran might feel emboldened by possession of a bomb. A nuclear Iran, this argument goes, would change the balance of power in the region and allow it to increase its training and material support to Hamas, Hezbollah, and various militias in Iraq. Some fear Iran would even seek to strengthen Shiite groups in Bahrain and Saudi Arabia.