“We got a leader in Iran who has announced that he wants to destroy Israel,” said President Bush in response to a question during his press conference yesterday. “So I’ve told people that if you’re interested in avoiding World War III, it seems like you ought to be interested in preventing them from having the knowledge necessary to make a nuclear weapon.”

Can Iran spark global conflict? Yes, but so can other nations, some of them far less dangerous than the regime run by Tehran’s atomic ayatollahs. It’s not only Mahmoud Ahmadinejad about whom we should be worried. Unfortunately, the international system is so fragile that almost any autocrat can commit the act that brings about global conflagration. Today, we see the same conditions that existed before World Wars I and II.

Before the Great War, as it was once known, there was a confusingly complex international structure that was too difficult for national leaders to comprehend or control. Moreover, grand alliances pulled nations into war when they might otherwise have remained bystanders to conflict. Before World War II, feckless Western leaders let tyrants commit aggression against their less powerful neighbors.

These same trends are now playing out while the American-led system fractures. The world can be stable in any type of system, yet it is rarely safe when transitioning from one type of structure to the next. The authoritarian nations, led by China and Russia, are drawing closer together, and the West’s leaders seem afraid to defend important principles.

Will we in fact enter a period of turbulence? There is one critical difference between this time and the periods before the two great conflicts of the last century. At least at this moment, Americans still have the power to preserve the peace. The real issue is whether we also have the will and imagination to do so.