At a meeting with reporters last week, President Bush said that "if you're interested in avoiding World War III, it seems like you ought to be interested in preventing [Iran] from having the knowledge necessary to make a nuclear weapon." These were not the barbs of some neoconservative crank or sidelined politician looking for publicity. This was the president of the United States, invoking the specter of World War III if Iran gained even the knowledge needed to make a nuclear weapon.

The American discussion about Iran has lost all connection to reality. Norman Podhoretz, the neoconservative ideologist whom Bush has consulted on this topic, has written that Iran's President Mahmoud Ahmadinejad is "like Hitler … a revolutionary whose objective is to overturn the going international system and to replace it in the fullness of time with a new order dominated by Iran and ruled by the religio-political culture of Islamofascism." For this staggering proposition Podhoretz provides not a scintilla of evidence.

Here is the reality. Iran has an economy the size of Finland's and an annual defense budget of around $4.8 billion. It has not invaded a country since the late 18th century. The United States has a GDP that is 68 times larger and defense expenditures that are 110 times greater. Israel and every Arab country (except Syria and Iraq) are quietly or actively allied against Iran. And yet we are to believe that Tehran is about to overturn the international system and replace it with an Islamo-fascist order? What planet are we on?

When the relatively moderate Mohammed Khatami was elected president in Iran, American conservatives pointed out that he was just a figurehead. Real power, they said (correctly), especially control of the military and police, was wielded by the unelected "Supreme Leader," Ayatollah Ali Khamenei. Now that Ahmadinejad is president, they claim his finger is on the button. (Oh wait, Iran doesn't have a nuclear button yet and won't for at least three to eight years, according to the CIA, by which point Ahmadinejad may not be president anymore. But these are just facts.)

In a speech last week, Rudy Giuliani said that while the Soviet Union and China could be deterred during the cold war, Iran can't be. The Soviet and Chinese regimes had a "residual rationality," he explained. Hmm. Stalin and Mao—who casually ordered the deaths of millions of their own people, fomented insurgencies and revolutions, and starved whole regions that opposed them—were rational folk. But not Ahmadinejad, who has done what that compares? One of the bizarre twists of the current Iran hysteria is that conservatives have become surprisingly charitable about two of history's greatest mass murderers.

If I had to choose whom to describe as a madman, North Korea's Kim Jong Il or Ahmadinejad, I do not think there is really any contest. A decade ago Kim Jong Il allowed a famine to kill 2 million of his own people, forcing the others to survive by eating grass, while he imported gallons of expensive French wine. He has sold nuclear technology to other rogue states and threatened his neighbors with test-firings of rockets and missiles. Yet the United States will be participating in international relief efforts to Pyongyang worth billions of dollars.