Gary Milhollin, the director of the Wisconsin Project on Nuclear Arms Control, which maintains the Web site Iran Watch, argues that even if the American and Israeli nuclear arsenals deter Iran’s use of a nuclear weapon, Iran might be in any case tempted to behave differently toward its neighbors.

“If Iran gets the bomb, we’re going to have a period of experimentation in the beginning, where Iran is trying to figure out how much power this new capability has conferred,” Milhollin says…

Milhollin worries about other unpredictable scenarios, such as miscalculation, in which bellicose statements from Iran and counterstatements from the U.S. and Israel might lead to a conflict that no one intended.

“At that point, you’re stepping into the unknown. And I think it would be very risky to assume that a combination of containment and deterrence would be adequate to protect us,” he says.