IF THE ANTIWAR CROWD and Democrats have their way, the United States will be Iran’s hostage once again. An immediate pullout from Iraq would be a victory for Iran, a regime that has declared its ambitions to wipe Israel off the map and establish a caliphate throughout the Middle East. If we allow democracy to be defeated in Iraq, it will only get harder to release Iraq and perhaps the greater Middle East from the grip of its would-be rulers in Tehran.

Decades ago, the United States underestimated the Ayatollah Ruhollah Khomeini’s appeal to the Iranian masses and his ability to convert the latent hostility to modernism into political clout. Khomeini overthrew the shah and took more than 50 Americans hostage, thus delivering a significant blow to U.S. prestige and clout in the Middle East.

Now the U.S. is underestimating Iranian President Mahmoud Ahmadinejad and his willingness to use proxies– Hamas in Gaza, Hezbollah in Lebanon and Muqtada Sadr in Iraq. In the short term, Iraqis, Lebanese, Palestinians and Israelis are paying for this sneaky strategy with their lives, but in the long term, it is the United States that will suffer the most.

Iranian leaders delivered a formal response Tuesday to the U.N. Security Council’s demands that Iran suspend uranium enrichment. They had been clear about what would be in that response for weeks: defiance and continuing assertions that its nuclear program is only about generating electricity, not bomb making. “The Islamic Republic of Iran has made its decision and, in the issue of nuclear energy, will continue its path powerfully,” said the Ayatollah Ali Khamenei, Iran’s supreme religious leader, on Monday.

Western diplomats in Iran believe Iran’s strategy is intransigence. Iran’s leadership is betting that the Security Council, and the nations of the West in particular, want to avoid another ugly confrontation in the Middle East, especially given the risky and open-ended situations in Lebanon and Iraq. The chaos there, according to the diplomats, has given an upper hand to the more hard-line members of Iran’s leadership.

In neighboring Iraq, Iran has bankrolled Sadr’s Al Mahdi militia and supported politicians in several Shiite parties. Iranian influence is already at a peak in the Shiite south, especially in Basra, where Iranian agents effectively rule the city. Iran has poured money into southern Iraq, providing reconstruction programs aimed at enhancing its reputation among the Shiite community, just as Hezbollah did in southern Lebanon. In return, Shiite militia are enforcing extremist versions of Islamic law in the region– there have been news reports of barbers being killed for shaving men’s beards, athletes being killed for wearing shorts and women threatened with death for not wearing veils.

Iraq is the crucial test of Iran’s ambitions. The majority of Iraqi Arabs share the basic Shiite creed with the majority of Iranians. Iraq and Iran share a long history of conquest and reconquest, of intertwined culture. However, many Iraqi Shiites do not share the fundamentalist theology and hegemonistic ambitions of Iran’s ayatollahs and its government. They are represented not by Sadr but by the Grand Ayatollah Ali Sistani, the revered and influential Shiite cleric and a voice of reason in Iraq.

It makes sense, therefore, that the first line of defense against Iran’s ambitions is a stable, democratic Iraq, which would provide a formidable counterbalance to Iran. A pro-Western Iraq that develops its economic ties throughout the Middle East and beyond would compete over growing markets for oil with Iranian economic interests. More important, a democratic Iraq would be a long-sought beacon for the oppressed Shiites of the world, an alternative to the appeal of extremist Iran.

The U.S. military’s presence in Iraq keeps Iran in check. An immediate pullout, as prescribed by antiwar liberals and demagogic Democrats, would leave Iraq to Iran, and to the likes of Al Qaeda. And that would be a hostage-taking far more harmful to the United States than the one that happened in Tehran nearly 30 years ago.