Not only has Tehran thumbed its nose at diplomatic efforts to settle disputes over its nuclear (weapons) program, now it's offering to share its nuclear know-how with others. At the United Nations last week, Iran's President, Mahmoud Ahmadinejad, said Tehran is ready - and willing - to share "peaceful" nuclear technology with other Islamic states.

Making matters worse, the U.N.'s International Atomic Energy Agency (IAEA) reported that Iran has already produced seven tons of uranium hexafluoride - enough precursor material to support the building of one nuclear weapon - since ending its moratorium on uranium-enrichment activities earlier this month.

Will the Iranian nuclear juggernaut be stopped before Tehran becomes a certified nuclear power - and spreads its atomic wares across the Muslim world? The next best chance to do that comes this week, when the 35-nation IAEA board of governors meets in Vienna.

The United States and like-minded nations (France, Britain, Germany, Japan, Australia) are trying to pressure Iran back to the nuclear negotiating table - or get the IAEA to (finally!) refer Iran to the U.N. Security Council for possible economic sanctions over its violation of Nuclear Non-Proliferation Treaty safeguards.

But not everyone is convinced; diplomatic deal-making over voting Iran to the Security Council is reaching a fever pitch. Tehran is seducing potential supporters with its significant energy resources, while flirting with Muslim members of the IAEA board (Yemen, Nigeria, Algeria) by offering to share its ill-gotten nuclear spoils.

In fact, late last week, opponents of referral were trying to delay consideration of Iran's nuclear program for at least a few weeks to give Iran time to return to negotiations, gather supporters or undermine Washington's position.

Big powers such as Russia, China and India are leaning against a quick referral. Beijing and Delhi thirst for Iranian oil and gas, while Moscow is eager to build/fuel Iran's Bushehr reactor. Venezuela, South Africa and Brazil are thinking about their own nuclear ambitions.

Despite threats to downgrade relations with the IAEA, Tehran is hinting at a compromise. Iran will invite Europe, Russia, China and South Africa to participate in nuclear joint ventures that would let Iran keep its nuclear fuel cycle, while calming fears that Tehran isn't diverting fissile material to a nuclear-weapons program.

But why should we trust Iran to cooperate with anyone, considering its record of resisting the IAEA over the last couple of years?

Even after 21/2 years of intensive, on-the-ground investigation, the IAEA says that many key aspects of Iran's (18-year, clandestine!) nuclear program remain murky due to a dearth of Iranian cooperation. In fact, even after 30 months, the IAEA still can't "conclude that there are no undeclared nuclear materials or activities in Iran."

IAEA head Mohamed El Baradei claims that Tehran continues to dodge questioning, even resisting IAEA requests to interview nuclear scientists. It also won't let the watchdog conduct a full inspection at other possible nuclear sites, such as Parchin.

Among the burning mysteries: a) how Iran developed its uranium-enrichment capability; b) what assistance Iran got from A.Q. Khan, the rogue Pakistani nuclear scientist; and c) was Tehran conducting nuclear work at Lavian-Shian before it was exposed as a possible nuclear site and bulldozed under in 2004?

There are also troubling questions about Iran's research on plutonium, which isn't generally used for nuclear reactor fuel, but is used in advanced nuclear weapons. The IAEA would also like to know why Iran has been experimenting with polonium, and attempted to buy beryllium - both used for triggering nukes.

Considering Iran's record of denial and deception, the United States and its allies in this effort are absolutely right to demand a full cessation of all Iranian enrichment-related activities, complete disclosure to the IAEA and a continuation of negotiations with the EU-3 (France, Germany, Britain) over its nuclear program.

Moreover, under no circumstances should Iran be allowed to develop or maintain a nuclear fuel cycle, which would allow it to manufacture or enrich its own nuclear fuel not just for civilian reactors, but also for bombs. The IAEA assessment makes it plain that there'd be no way to verify that Iran isn't diverting nuclear material to a military program.

Without question, the Iranian nuclear issue has reached critical mass. What happens in Vienna over the next couple of weeks will determine not only the IAEA's - and the United Nations' - credibility in nuclear nonproliferation, it will, more importantly, determine Iran's nuclear fate - and its ability to share its nuclear know-how with others.

Peter Brookes, a Heritage Foundation senior fellow, hosts "The Brookes Report" on WMET radio in Washington D.C.