A look at the priorities and limitations of the major actors suggests why something so universally endorsed is proving so difficult:
United States: In the U.S., Iran is Enemy No. 1, not least for its terrorism connections, threats to Israel and humiliating 1979 hostage taking. Yet trapped in Iraq and anxious to rebuild America's global standing, the Bush administration now places priority on consensual diplomacy.
Empowering them are CIA estimates that still put the Iranian weapons timeline at least three to eight years off. So, encouraged by the economic pain that limited financial sanctions have already inflicted, America will push for the strongest possible UN resolution to up the pressure, in hopes Iran will calculate that the costs are too high.
France: France is emerging as the leading hardliner on Iran. It fears Iran's regional troublemaking and potential hegemony, and remains scarred by Iran's 1991 assassination of former prime minister Shapour Bakhtiar in Paris. France's vehement opposition to Iran's nuclear program also reflects a concern not to see France's own status as a nuclear-weapons state diluted. President Nicolas Sarkozy appears more staunch against Iran than was Jacques Chirac. Importantly, Sarkozy's key advisers are all seeped in the Iran issue and, for once, in sync.
Britain: With a new team, Britain is no longer in the driver's seat in the Security Council negotiations, and Jack Straw's re-emergence as leader of the House of Commons could tug Brown toward the "military options off the table" prescription that helped trigger Straw's dismissal as foreign secretary last year. The British-drafted offer to Iran last month - to forego additional sanctions for a short period if Iran foregoes additional centrifuges - may reflect the new team's greater willingness to compromise, although they insist it is only a trade-off of process for substance.
Germany: Germany has long been the weak link in the European engagement strategy. Protective of commercial interests in Iran (nearly €5 billion in annual trade, seven times that of Britain), Berlin resists American calls for ending trade credits for Iran. Germany's nonproliferation advocacy reflects a historical dovish orientation.
Berlin's foreign policy priority to maintain a common European stance trumps its inclination to give Iran the benefit of the doubt. Yet Germany will still be inclined to give priority to negotiations, almost for their own sake.
Russia: Russia's stance is the most complicated. Trade interests, jitters about Iran's potential to make trouble along Russia's southern flank, real concerns about another war in its neighborhood and the desire to exercise an independent leadership role all give the Kremlin reason not to push Iran into a corner.
Moscow is increasingly frustrated by Tehran's intransigence, however, and worried about the regional domino effect of a Persian bomb. The nuclear agency Rosatom is ready to drop the Iran account for more lucrative markets elsewhere, and President Vladimir Putin privately disparages Mahmoud Ahmadinejad as having a martyr complex. As long as its oxen are not gored, Russia is likely to support new sanctions.
China: China is the potential odd man out. Once able to hide behind Russia's protection of Iran, China may soon be the only opponent of harsh sanctions.
China knows that additional sanctions will see more Chinese traders named as violators. Meeting long-term energy needs is a top priority, so it cannot afford to antagonize Iran. China now accepts the inevitability of UN sanctions, but it is easily co-opted by Iranian tactics.
Gulf States: Saudi Arabia, which until a year ago declared no interest in nuclear power, has now banded with the other Gulf states in pursuing a nuclear security hedge against Iran. Concerned about Shiite hegemony, the Gulf states welcome closer security ties with the U.S. They want Iran's nuclear aspirations checked.
Israel: Israel's preoccupation with the existential threat from Iran transcends personalities. The Israelis cannot afford the chance that Ahmadinejad's threats to wipe it off the map were not just mistranslated hyperbole.
However, they want to avoid pushing Bush into another pre-emptive war with counterproductive consequences, and thus seek every possible pressure point to stop Iran before it is too late.
"Too late" means when Iran can churn out highly enriched uranium - a milestone that may be reached within a year. This timeline is not long - on July 31, it will already be a year since the Security Council mandated Iran to suspend enrichment, and too little has been done to enforce it.
The key is for all parties to hang together in passing and enforcing biting sanctions - and quickly. The Security Council must also emphasize the benefits available if Iran foregoes uranium enrichment. Being ready to do both helps raise the common denominator.
Mark Fitzpatrick is senior fellow for nonproliferation at the International Institute for Strategic Studies and formerly was a U.S. Deputy assistant secretary of state for nonproliferation.
