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.