If the six-nation forums dealing with Iran and North Korea suffer comparable failures, the consequence will be a world of unchecked proliferation, not controlled by either governing principles or functioning institutions. A modern, strong, peaceful Iran could become a pillar of stability and progress in the region. This cannot happen unless Iran's leaders decide whether they are representing a cause or a nation - whether their basic motivation is crusading or international cooperation. The goal of the diplomacy of the Six should be to oblige Iran to confront this choice.