As the conflict in Iraq reminds us, nation building confounds its architects' designs with almost predictable regularity. Investments of time, resources, and specialized knowledge have not enabled large-scale political engineering. Instead, would-be nation builders have been frustrated by a proliferation of unintended consequences and their inability to elicit societal participation in their projects. Results depend more upon initial conditions prior to an intervention than the nation builder's exertions upon arrival.

Hence, the U.S. has performed most poorly when its mission required the most work (e.g., Somalia, Haiti, Iraq). Conversely, it has done best where it did less (Germany, Japan), deferring to old-regime civil servants and upgrading already functional institutions. Given the humbling record of Western powers at navigating the perils of macro-level political planning, the "how" of nation-building should be considered, in the formulation of Defense Secretary Donald Rumsfeld, a known unknown.

More likely, it is a known unknowable. The extent of unintended consequences and contingency in largescale political engineering makes disappointment certain and disaster likely.

Twentieth-century experiences belie the notion that nation-building successes will solve the problem of state failures. Forces trying to impose regime change and raise new state structures immediately grapple with societal inertia and their own deficit in understanding local politics.

This dilemma pushes would-be nation builders down one of two undesirable paths. Either they recognize their inability to restructure indigenous political arrangements or they attempt to do so in vain. Despite plans of change at the outset of nation building, those executing the project soon embrace a change of plans.

Thus, even the most committed states have been hampered by an inability to develop political capacity on the ground and improve upon the initial endowments of the country being occupied. Institutional value-added has been minimal, reflecting the problem of state instability back upon those who expected to solve it.

These patterns raise serious doubts about the chances of success in even the most well-intentioned of regimechange missions. They demarcate the limits of projecting state power abroad, whether for humanitarian or security purposes. The failures of imposed regime change lead to the conclusion that indigenous gradual political development-with all of its potential for authoritarianism and civil unrest-may be the optimal path for sustainable democratization and state building.

When comparing the uneven history of post-colonial development with the poor record of nation building we are left paraphrasing Churchill's endorsement of democracy as the worst kind of government except for the alternatives: Sovereign political development may be the worst form of government except for all those kinds of nation building that have been tried.

Infrastructural weakness is not a technical problem surmountable through systematic review of prior experiences. Indeed, the notion of "learning past lessons" deceptively implies that the current generation of academics and policymakers can succeed where their predecessors failed. The idea that nation building is a flawed but salvageable project prejudges its fundamental viability.

Once we have set our sights on rescuing an enterprise that has repeatedly frustrated its architects and their subjects, we screen out alternatives that more effectively serve the same development goals. We also risk funneling research down an intellectual cul-de-sac, at great cost in time, resources, and lives lost for those participating in failed regime-change missions. Therefore, a more productive direction for contemporary interest in nation building may mean backing up and reassessing the core problem of weak states, on one hand, and the limits of foreign intervention, on the other. Ensuring a positive impact on the country considered for intervention requires orienting the enterprise away from the takeover of state functions and toward the short-term provision of aid to local communities.

Apart from the futile pursuit of infrastructural power or the doomed deployment of despotic power (coercion), one can envision a third kind of influence, "regenerative power," which is exercised during relief efforts, such as emergency assistance following natural disasters.

Regenerative power involves neither the adoption of domestic state functions nor physical coercion. It denotes the ability of a state to develop infrastructure under the direction of the local population. For example, it means rebuilding a post office, but not delivering the mail. It is typified by the U.S. response to natural disaster relief within its own borders and abroad.

Regenerative power turns nation building on its head. Rather than imposing a blueprint from outside, participants respond to the needs of the affected community. It is restorative rather than transformative. There is no preexisting master plan for what the "final product" will be, but rather an organically evolving process in which the assisting group serves at the direction of the people being assisted.

The exercise of regenerative power is inherently limited in scale since it depends on local engagement rather than elite planning. It is inimical to macro-level ambitions but it also acquires a bounded effectiveness that imposed regime change lacks. Where nation building attempts to overwrite existing organization and only belatedly incorporates local understanding, disaster relief efforts and regenerative projects begin from the assumption that local communities know best their own needs. Existing social networks and patterns of authority are an asset, not a hindrance, and local know-how offers the principal tool for resolving local crises.

Rather than pursuing the often destructive delusion of interventionist state transformation, regenerative power starts from an interest in using state power for constructive purposes and a sober assessment of the limits of that aim. The assisting foreign groups serve under the direction of indigenous political leaders toward the achievement of physical reconstruction and emergency service provision.

With remarkable prescience Rumsfeld commented in October 2001, "I don't know people who are smart enough from other countries to tell other countries the kind of arrangements they ought to have to govern themselves."

The experience of twentieth century U.S. interventions and ongoing operations in Iraq supports his insight. Proponents of nation building or shared sovereignty arrangements have exaggerated the ability of powerful states to foster institutions in developing countries. The empirical record, from successful outcomes in Germany and Japan to dismal failures across the global south, shows the societies alleged to be most in need of strong institutions have proven the least tractable for foreign administration. Rather than transmitting new modes of organization, would-be nation builders have relied upon existing structures for governance.

This dependence on the very context that was intended for change reveals how little infrastructural power nation builders wield. They are consistently unable to implement political decisions through the local groups. Contrary to recent arguments that sustained effort and area expertise can enable success, nation building has foundered despite such investments.

Understanding that nation building is a "known unknowable" is crucial for redirecting intervention where it can be more effective. Advocates of humanitarian assistance should consider the merits of smaller, regenerative projects that can respond better to uncertainty and avoid the perils of large-scale political engineering.

Even when the European-Iranian agreement to halt Iran's uranium-enrichment program looked solid, the United States was blunt in its disapproval. The ink was barely dry on the accord when the Bush administration, it appears, began trying to derail it.

First, rather than endorse the accord, Secretary of State Colin Powell essentially accused the Iranians of lying when they said their nuclear program was for peaceful purposes. He announced that new intelligence showed Iran is developing a nuclear warhead to arm its Shahab-3 ballistic missiles. Then, at a Nov. 20 meeting of heads of state in Santiago, Chile, President Bush stated unequivocally that Iran is trying to build a nuclear weapon.

Why would the administration take such a combative stance? Because hard-liners within the administration thought Tehran would use the settlement to buy time for building nuclear weapons, and that the United States would be better off bombing Iran's suspected weapons sites.

Proponents of using military force against Iran have not yet won the argument within the Bush administration. But the past two weeks of strong pronouncements about the threat Iran poses suggest that the military option may be gaining ground. And Iran's last-minute attempts to maintain some enrichment capabilities -- which by press time Friday were threatening to kill the European agreement -- no doubt strengthened the hard-liners' hand.

Before the United States even considers such a drastic step as airstrikes against suspected nuclear weapons sites -- or even trying to compel the United Nations to endorse new economic sanctions against Iran -- it is essential that our leaders be clear about what they are trying to accomplish in Iran and whether such actions will help or hurt.

If the ultimate goal is to create a democracy -- one that would not fear the United States and therefore have less use for the bomb -- then dual-track diplomacy with Iran's government and with its people is more likely to work than military action.

Probably the most important question the administration's leaders should ask themselves is whether Iran, even a nuclear-armed Iran, poses a direct threat to the United States and its allies.

The answer, we believe, is no.

The mullahs who rule Tehran long ago gave up their ideological quest to "export'' revolution. Like the last generation of octogenarians who ruled the Soviet Union, Iran's leaders today want nuclear weapons as a means to help them preserve their power, not to help them spread their model of theocratic rule to other countries.

Deterrence works

In other words, even if Iran's rulers succeeded in building nuclear bombs, they would be very unlikely to take on the United States and its vast nuclear arsenal or to attack Israel. (The mullahs in Tehran understand that any nuclear attack against Israel would trigger full retaliation from the United States.) In dealing with Iran, deterrence works.

Tehran would also be unlikely to pass a bomb to Islamist terrorists, despite its support of Arab terrorist organizations that continue to attack Israel. One reason, again, is deterrence. Iran's rulers know that the United States would probably be able to trace the weapon back to them and retaliate.

The threat of a nuclear Iran comes, instead, from the reaction it is almost sure to spark in the region and the world, possibly sending Egypt and Saudi Arabia on their own quests for nuclear weapons.

Such an arms race would undermine the longstanding Treaty on the Non-Proliferation of Nuclear Weapons, an agreement signed by nearly 190 countries, that has proved indispensable in preventing the spread of nuclear weapons.

Bush administration hard-liners want to save that arms-control treaty by using arms. In advocating a "surgical'' military strike against Iran's most important nuclear facilities, including the once hidden enrichment plant in Natanz, they cite Israel's airstrike against Iraq's nuclear complex at Osirak in 1981 as a model of success. They argue that an American (or Israeli) strike would not end Iran's nuclear aspirations, but would dramatically slow its program and make the mullahs reconsider the costs of trying to restart it.

Attack would backfire

But a pre-emptive military strike would instead do just what the hard-liners in Tehran hope for: It would unite their people behind them.

Even a precise bombing campaign would kill hundreds if not thousands of innocent Iranians; destroy ancient buildings of historical and religious importance; trigger an Iranian counterstrike, however feeble, against American targets and friends in the region, and spur the mullahs to increase their direct support for American enemies in the Shiite part of Iraq.

Even more important, an attack would only encourage Tehran to redouble its efforts to build a bomb, just as Saddam Hussein sped up his efforts after the 1981 strike. It would also hurt the democratic opposition movement inside Iran, which is already in retreat and cannot afford another setback. After an attack, Iranians, not unlike Americans, are sure to rally around the flag and their government.

If the administration decides, in the end, that American military options are limited and counterproductive, the only serious way to impede the development of Iranian nuclear weapons is through negotiation. Iran's recent accord with France, Britain and Germany is only temporary, and negotiations are expected to continue.

If the United States were to jump in now, it could try to ensure that our European allies accept nothing less than a permanent and verifiable dismantling of Iran's enrichment capabilities, as well as banning any plutonium production.

Allowing the Iranians to enrich even some uranium, which they say will be used merely to feed their nuclear power plant, makes it too easy to cheat. To make the deal work, the United States would need to join with Europe, Russia and China in pledging to guarantee Iran a permanent and continuous supply of enriched uranium. To make the deal even more attractive, the fuel could be offered at reduced prices.

Even under the strictest inspection regime, Iran's leaders will cheat, as they have often done in the past, and they will eventually divert enriched uranium from peaceful to military purposes. But the harder and more transparent the allies can make it, the longer it will take Iran to begin building bombs.

In the long run, the world's only serious hope for stopping Iran from developing nuclear weapons is the development of a democratic government in Tehran. A democratic Iran will become an ally of the Western world no longer in need of a deterrent threat against the United States.

Democracy in Iran therefore obviously serves U.S. national interests. Yet Bush administration officials (as well as their predecessors in the Clinton, Bush and Reagan administrations) have not succeeded in developing a strategy for advancing the cause of Iranian democracy.

New strategy

What is needed is a radical new approach that would nurture change from within the country, in alliance with Iran's democratic movement, rather than impose change from without.

A first step would be to establish an American presence in Tehran, as many in Iran's democratic opposition have proposed. Now decades old, the U.S. policy of isolating Iran has not weakened but instead strengthened its autocratic government.

Of course, we are not suggesting that the United States open an embassy in Tehran and turn a blind eye to human rights abuses; that would only contribute to the further consolidation of the mullahs' hold on power. But we are suggesting a new strategy that would allow American government officials, as well as civic leaders, academics and business people, to engage directly with Iranian society.

This engagement cannot occur on a widespread scale without some level of diplomatic relations and some revision of the American sanctions against Iran. Then, more Western foundations would be able to make grants to pro-democracy Iranian organizations, while business people -- and especially the Iranian-American business community in the United States -- would be able to leverage their capital and know-how to influence economic and political change inside Iran. A U.S. presence in Iran would, not incidentally, also enhance the West's ability to monitor Iran's nuclear program.

Critics of engagement argue that diplomatic relations with Iran will reward this "axis of evil'' member for years of supporting terrorism and pursuing nuclear weapons. In fact, an American presence in Iran is the mullahs' worst nightmare.

Iran's government has long used its ongoing tensions with the United States, as well as the embargo, as an excuse for the economic difficulties that are, in fact, the direct results of the regime's incompetence and corruption. Tehran's leaders have conveniently labeled nearly all of their opponents as "agents of America.''

Most important, part of the regime's self-declared legitimacy lies in its claim to be the only Muslim country fighting what it sees as U.S. imperialism. If the United States could prove it's not an enemy of the Iranian people, the legitimacy of Iran's leaders would diminish.

Reagan's course

In the first years of his presidency, Ronald Reagan labeled the Soviet Union the "evil empire'' and went out of his way to avoid contact with such a regime.

Over time, however, Reagan charted a new course of dual-track diplomacy. He engaged Kremlin leaders (well before Gorbachev) in arms control, while also fostering contacts and information flow between the West and the Soviet people in the hope of opening them up to the possibilities of democracy.

In the long run, it was not arms control with the Soviets, but democratization within the Soviet Union, that made the United States safer.

If George W. Bush desires a foreign-policy legacy as grand as Reagan's, now is the time to think big and change course as dramatically as Reagan did.