For the moment, administration officials are hoping that "targeted" sanctions aimed directly at Iran's leadership will compel a compromise. The United Nations Security Council's recent decision to tighten existing sanctions on Iran by prohibiting dealings with 15 individuals and 13 organisations aims at precisely that. But, while some within the US government argue that similar sanctions induced North Korea to compromise on its nuclear programme, there are several reasons why the same strategy is unlikely to work with Iran.

First and foremost, targeted sanctions did not, in fact, really work with North Korea. The freeze on US$25 million (Bt870 million) of the leadership's assets held at Banco Delta Asia in Macau has certainly irritated the North Koreans. But the asset freeze did not prevent Kim Jong-Il from ordering a ballistic missile test last July or an underground nuclear test in October.

Instead, North Korea's willingness to resume negotiations partly reflects the Americans' decision to stop insisting on the "complete, verifiable, irreversible dismantlement" of North Korea's nuclear programme as a pre-condition for talks on normalising relations. The Bush administration has accepted that North Korea is a nuclear power and that outsiders can do little about it, so the United States has shifted its diplomatic stance from the hard-line Japanese approach to the more flexible and stability-oriented Chinese position.

That shift is understandable. Given its simultaneous military commitments in Iraq and Afghanistan, together with North Korea's demonstrated nuclear capability, the Bush administration can't credibly threaten Kim with force. Sanctions have rattled the North Korean leadership, but not nearly enough to compel them to surrender fully the nuclear programme, which is their ultimate guarantee of security.

At the same time, the North Koreans' willingness to make a deal also reflects China's decision to put its foot down. China remains the only foreign power with any real leverage over Kim's government. Exasperated by Kim's refusal to ease international tensions, Chinese officials have made clear their refusal to protect and subsidise North Korea's elite if it continues to push the US toward confrontation. The Chinese can't force Kim to disarm fully, but they can persuade him to negotiate with a now more flexible US.

As a result, the US and North Korea have agreed a deal that differs from the Clinton-era "Agreed Framework", mainly because North Korea now has a track record as both a deal breaker and a nuclear weapons state. Having returned to the bargaining table in a position of strength, North Korea now hopes to secure a compromise that frees up the leadership's assets and brings new benefits that help buttress the regime a little longer. As long as the Chinese talk tough and the US remains willing to negotiate, the agreement may hold. But neither diplomatic stance is likely to continue indefinitely.

In any case, none of this will help the Bush administration with Iran. No outside actor has the leverage with Iran that China has with North Korea, and even if the US offered Iran a more conciliatory approach, the Democratic-led Congress isn't likely to follow suit. Buffeted by criticism that their position on the war in Iraq is incoherent and that they are soft on security threats, the Democrats appear determined to ratchet up pressure on Iran, favouring much broader sanctions than the Bush administration has proposed.

For example, House Foreign Affairs Committee Chairman Tom Lantos has introduced legislation that would extend the extra-territorial reach of US law to foreign governments' export credit agencies, financial institutions, insurers, underwriters, and guarantors. It would bar foreign subsidiaries of US companies from investing more than $20 million in Iran's energy sector, and would eliminate the president's authority to waive these penalties. It would also designate Iran's Revolutionary Guard as a terrorist group and impose further limits on exports to the country's civil aviation industry.

 Moreover, Republicans are getting in on the act. Representative Ileana Ros-Lehtinen has introduced legislation that would require US government pension funds, private pension funds, and mutual funds sold or distributed in the US to divest from companies that invest more than $20 million in Iran.

Finally, just as Iran faces no China - an outside player with considerable domestic influence - North Korea faces no Israel, a neighbour that believes its security could depend on an act of military pre-emption. Israel does not want to take on Iran without US support and will maintain pressure on both Congress and the president to threaten Iran with every means at its disposal.

The appeal of targeted sanctions against Iran is obvious: they are meant to help the administration avoid military action, which could create more problems than it solves. They allow the White House to argue that it means to undermine Iran's leadership, not its people. They are also much more likely to win international support than sanctions that would remove Iran's oil and gas supplies from the international marketplace.

But the chances are slim that sanctions, whether targeted or otherwise, can undermine the consensus within Iran in favour of the nuclear programme. As in North Korea, a nuclear capability constitutes a powerful symbol of the country's sovereignty and international clout - and would be the ultimate guarantee that America could never do there what it has done in Iraq.

Sanctions give lawmakers and diplomats plenty to talk about. But unless a sea change occurs in Iranian domestic politics, they will merely postpone the difficult (and increasingly likely) choice between military action and accepting a nuclear Iran.

Ian Bremmer

New York

Ian Bremmer is president of Eurasia Group, a global political risk consultancy, and author of "The J Curve: A New Way to Understand Why Nations Rise and Fall."

Copyright: Project Syndicate.