The Europeans were secretly relieved that Russia blocked Iran’s referral to the UN Security Council. Even for the U.S., delay serves their focus on efforts to stabilize Iraq.

This represents the time required to complete construction and conduct trial operations of a pilot scale centrifuge enrichment plant (currently planned to house 1,000 centrifuge machines) and then operate the plant long enough to produce 20-25 kilograms of weapons-grade uranium, enough for a single simple implosion design.

Instead, Iran has designed its nuclear program to look on paper like it is intended to produce low enriched uranium for nuclear power fuel, rather than high enriched uranium for weapons, which means sacrificing certain efficiencies.

From a purely technical standpoint, it will likely take more than a decade for Iran to complete an industrial scale enrichment plant (planned for 50,000 centrifuge machines).

Wasting no time

Once operational, however, such a plant would create a strong nuclear breakout option, capable of producing enough weapons-grade uranium for a nuclear weapon within a few weeks or even days of operation.

Similarly, it's likely to be more than a decade before Iran can complete facilities to produce and separate plutonium in significant quantities for nuclear weapons.

Diplomatic maneuvers

None of these technical barriers are fatal, but they create space and time for international efforts to deny Iran a nuclear weapons capability. Unfortunately, the effectiveness of diplomatic efforts over the past two and a half years — since Iran's secret nuclear activities were first publicly revealed — has been decidedly mixed.

Both Moscow and Beijing share the Western view that Iran is seeking to develop nuclear weapons — and they have privately warned Iran not to resume enrichment.

On the one hand, to avoid referral to the UN Security Council — which Tehran fears could lead to political isolation, economic sanctions and even military attack — Iran has been compelled to cooperate.

Iran thus allowed investigations by the International Atomic Energy Agency (IAEA) into its nuclear secrets — and suspended key elements of its enrichment activities since October 2003 in a series of agreements with the so-called EU-3 (consisting of the UK, France and Germany).

Basically, the Europeans told Iran they would block U.S. efforts to refer Iran to the UN Security Council if Iran continued to cooperate with the IAEA and suspended certain nuclear activities as a "temporary" confidence-building measure.

Some, but not all

On the other hand, Iran has adamantly rejected European demands to permanently abandon its enrichment program in exchange for helping Iran develop its nuclear power industry — including purchase of European power reactors and assurances of fuel supply.

In other words, Iran has made tactical concessions — under pressure — to accept limits or delays in its nuclear fuel cycle program, but it has not been willing to abandon the program altogether at any price.

Iranian calculations

This seems to reflect a deeply held and long-standing conviction among all major elements of Iran's leadership. In their collective mind, Iran needs to acquire a nuclear weapons option, although Iranians claim there are different views on the wisdom of actually building nuclear weapons.

A permanent solution will probably have to await more fundamental changes in the Iranian government and its relations with key outside powers.

Under these circumstances, the immediate diplomatic objective is to maintain pressure to delay the program — by keeping the suspension in place and requiring Iran to cooperate with the IAEA investigations.

In this respect, however, Tehran calculates that the balance of power is shifting in its direction, reducing the risk of referral to the UN. From Tehran's standpoint, the tight oil and gas market affords protection against the risk of economic sanctions — and the U.S. entanglement in Iraq provides protection against the risk of U.S. military attack.

As a consequence, Iran has decided that it is safe to break their suspension agreement with the Europeans.

Divide and conquer tactics?

Using salami tactics, Iran calculates that it can defeat Western efforts at the IAEA Board of Governors meeting to refer Iran to the UN Security Council. So far, it appears that Iran's gamble is working.

At the last IAEA Board of Governors meeting, Russia threatened to vote against the resolution. Moscow argued against the resolution on the grounds that Iran would retaliate by suspending some IAEA inspections or resuming enrichment activities, and the Council was in a poor position to respond because there is no political support for tough sanctions.

Much needed respite

In fact, the Europeans were sympathetic to these arguments and secretly relieved that Russia blocked referral.

In the mind of Iran’s leaders, Iran needs a nuclear weapons option — although Iranians claim there are different views.

Even for the United States, delay serves Washington's focus on efforts to stabilize Iraq. And it helps with destabilizing Syria, which — if successful — will weaken Iran's strategic position and improve Washington's ability to intimidate Iran over the nuclear issue.

Given all that, Iran calculates that it has a window of opportunity to advance its nuclear program. In particular, Iran is free to continue working to fix problems at its conversion facility and build up a stockpile of UF6 feed material.

More dangerously, Iran may decide at some point that it is strong enough to risk a resumption of some enrichment activities.

A dangerous hypothetical

Following its usual salami tactics, for example, Iran might decide to resume some enrichment research and development or production of additional centrifuge components, while maintaining the suspension on the actual completion or operation of the pilot enrichment plant.

During this delicate period, the key challenge for the United States and Europe is whether they can mobilize strong international agreement that enrichment is a red line. This is all the more difficult since they failed to enforce the previous hurdle — conversion of uranium — as the trigger for referral.

Russia and China in the middle

The key is Russia and China. Certainly, both Moscow and Beijing share the Western view that Iran is seeking to develop a nuclear weapons capability — and they have privately warned Iran not to resume enrichment.

A large-scale enrichment plant would create a strong nuclear breakout option, capable of producing enough weapons grade uranium for a nuclear weapon within a few weeks — or even days.

At the same time, they avoid referral to the Security Council, which could lead not only lead to a confrontation. Worse, it would force them to choose between good relations with Iran on the one hand — and relations with the United States and European powers on the other.

Clearly, the best way to avoid a crisis is to convince Moscow and Beijing that it is in their direct interest to warn Iran not to aggravate the situation by resuming enrichment, which would lead to UN referral.

Confronted with such a threat, Iran may decide that it has no choice but to keep the suspension in place for the time being — rather than risk the consequences of referral to the Security Council.

Buying time

The best outcome diplomacy can achieve under current circumstances is to buy time by delaying the resumption of Iran's enrichment program. The most effective instrument we have to achieve that objective is a credible threat of referral to the Security Council.