If Iran cannot be peacefully convinced to curtail its nuclear program, the president could soon be faced with a hugely consequential decision: attack Iran in an attempt to prevent it from acquiring nuclear weapons, or recognize that it could do so and embrace deterrence and containment instead. By staking American credibility on a policy of prevention at all costs, Obama may end up believing he has to choose war. But he would be wrong, because deterrence (threatening devastating retaliation) and containment (blunting the spread of Iranian power and influence) may in fact be more prudent than preventive attack.