President Mahmoud Ahmadinejad spoke on Tuesday before a United Nations panel, blaming nearly all the suffering of the world on the free world and capitalism. Such displays are as provocative as they are defiant, and they are only the latest in a long progression of menacing behavior that causes me and many of my fellow Christian leaders to be gravely concerned at the prospect of Iran, the leading state sponsor of terrorism in the world, obtaining nuclear weapons.

I have long supported peaceful and diplomatic efforts to avert an Iranian nuclear crisis. I and my fellow Christian leaders have strongly supported the passage of additional economic sanctions against Iran by the United States, European Union, and the United Nations. But Iran continues to mock the international community’s opposition to its nuclear programs.

Time is running out. The International Atomic Energy Agency (IAEA) reports Iran is systematically denying inspectors access to key nuclear facilities and refusing to answer questions about its accelerated enrichment of uranium. According to the IAEA, Iran has already processed enough uranium at its main facility in Natanz for two nuclear weapons and is actively pursuing advanced ballistic missile technology enabling it to deliver a nuclear warhead.

Iranian duplicity is nothing new. A year ago Western intelligence agencies discovered a secret nuclear facility at Qum located inside a military base operated by the Iranian Revolutionary Guard. Iran failed to disclose its existence to the international community, a clear violation of its obligations. There are now reports that Iran may have built yet another secret nuclear facility near Qazvin, 120 miles west of Tehran.

It is clear that Iran, whose president Mahmoud Ahmadinejad denies the Holocaust and has vowed to wipe Israel off the map, intends to produce nuclear weapons. The acceleration of its uranium enrichment and advanced military applications suggest we are in the eleventh hour.

Ahmadinejad is on U.S. soil, here to address the United Nations General Assembly on Thursday afternoon.  We can expect him yet again to mock the civilized world’s efforts to prevent his regime from obtaining nuclear weapons, a development that will destabilize the region, threaten the United States and our allies, and begin a nuclear arms race in the most dangerous part of the world.

I and my fellow Christian leaders are calling on President Obama to act immediately and decisively on this gravely serious matter. Specifically, we call on him to:

 Clearly lay out the case against Iran’s reckless actions, publicly correct President Ahmadinejad’s lies and dissembling and ensure that senior administration officials do everything to ensure that the American public is well-informed about the direct dangers that Iran’s nuclear weapons program presents to U.S. security and the world

 Strictly and fully enforce all sanctions against the Iranian regime, including preventing the foreign subsidiaries of U.S. corporations from doing business with Iran, and ensure our allies to do the same.

 Ensure that all member nations of the United Nations strictly enforce sanctions against Iran and make clear than non-compliance is unacceptable to the United States as well as a violation of international law.

The Iranian regime is the world’s leading state sponsor of terrorism, it has brutally repressed internal democratic opposition, it persecutes women and religious minorities, and it openly advocates the destruction of Israel. President Obama must lead the nation and the world against this grave threat to peace.

Pastor Jim Garlow of Skyline Church in La Mesa, Calif. is an advisory board member of Christian Leaders for a Nuclear-Free Iran, an ad hoc coalition of evangelical, Roman Catholic and other faith leaders calling for urgent action to prevent Iran from obtaining nuclear weapons.

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