You may disagree with Alan Dershowitz that the Iraq War was a mistake (I do), but his coldly realistic analysis of the Iran situation is convincing and disturbing: We can’t attack Iran. (Free registration required. Hat tip: Allah.)

Face it. Iran will get the bomb. It has already test-fired rockets capable of targeting the entire Middle East and much of southern Europe. And it claims to have 40,000 suicide volunteers eager to deploy terrorism — even nuclear terrorism — against its enemies. With a nuclear capacity, the Islamic Republic of Iran will instantly achieve the status of superpower to which Iraq aspired.

Nothing will deter Iran. Sanctions are paper protests to an oil-rich nation. Diplomacy has already failed because Russia and China are playing both sides. Sabotage, bribery — even assassination of nuclear scientists — may delay but will not prevent Iran from becoming a nuclear power. That leaves military threats and, ultimately, military action.

First, consider military threats. They are already coming from two sources: the US and Israel. Neither is working, for very different reasons.

The Iranians would probably give up their nuclear weapons programme if their leaders truly believed that refusal to do so would produce an Iraq-like attack — an all-out invasion, regime change and occupation. Leaders, even religious leaders, fear imprisonment and death. Only the United States is capable of mounting such a sustained attack.

But the continuing war in Iraq has made it impossible for the US to mount a credible threat, because American public opinion would not accept a second war — or so the Iranians believe. Moreover, America’s allies in the war against Iraq — most particularly Great Britain — would not support an attack on Iran.

That is precisely why the Bush administration is barking so loudly. It wants to convince the Iranian leadership that it is preparing to bite — to attack, invade and destroy their regime, perhaps even with the use of tactical nuclear weapons. But it’s not working. It is only causing the Iranian leaders themselves to bark louder; to exaggerate their progress towards completing a nuclear weapon and to threaten terrorist retaliation by its suicide volunteers if Iran were to be attacked.

The war in Iraq is a two-edged sword when it comes to Iran. One edge demonstrates that the US is willing and able to topple dictatorial regimes which it regards as dangerous. That is the edge the Bush administration is trying to showcase. The other edge represents the failure of Iraq — widespread public distrust of intelligence claims, fear of becoming bogged down in another endless war, strident opposition at home and abroad. That is the edge being seen by the Iranian leaders. The US threat is seen as hollow.

That last paragraph is especially relevant in the context of the present debate over the leaking of classified information during wartime. Our enemies are clearly exploiting this media-enabled weakness—and the media are just as clearly not going to exercise judgment in a profit-driven environment where getting the story out as quickly as possible is all that matters, even if—especially if?—it damages national security. Ahmadinejad and the mullahs have already experienced American weakness at its weakest, during the Tehran embassy hostage debacle, and what they see in America today is bringing back fond memories for them.

In a very real way, mainstream media’s culture of “If It Bleeds It Leads” is becoming a major liability in the clash of civilizations.