President Barack Obama is pursuing a policy of foreign engagement of adversaries and enemies.

The United States has reached out to Iran, pushed the "reset" button on relations with Russia, and tried to nudge China toward greater cooperation. Obama has also engaged North Korea and Cuba, and even Burma and Syria.

In 1940, with the publication of Guilty Men , Prime Minister Neville Chamberlain's engagement policy was depicted as naïve and wishful thinking. In 1976, candidate Ronald Reagan argued that President Richard Nixon and his Secretary of State Henry Kissinger's engagement policy of détente made the United States "number two in a world where it is dangerous if not fatal, to be second-best."

Criticism of Obama's foreign policy is similar. According to Robert Kagan, the Obama administration's new strategy entails "accommodating the world's rising powers." For other scholars and policymakers, Obama's foreign policy is a realistic whittling down of global aspirations to a core set of goals reflecting an assessment of available resources (also known as selective engagement), a shift in global balance of power (including soft and perhaps even hard balancing against the United States), a redefinition of American power, and a more limited view of the war on terrorism.

Britain's 1930s grand strategy of Limited Liability and America's 1970s détente grand strategy also called for engaging the enemy in order to reduce the number of foreign threats to an affordable level, conserve financial strength, and restore the balance between financial capabilities and global commitments.

As part of its grand strategy, Britain extended credits, loans, trade concessions, market guarantees, and export earnings in sterling to Germany and Japan. The United States proposed or extended capital and technology, Export-Import Bank financing, Most Favored Nation (MFN) tariff treatment and long-term credit to the Soviet Union. The United States granted China MFN trading status, foreign investment and Export-Import Bank financing.

Scholars and policymakers have depicted Britain's and the United States' trade concessions and commercial inducements to their adversaries as appeasement. Despite the aggregate material power and threat, British and American leaders identified moderate political and societal leaders in Germany, the Soviet Union, China and Japan.

The intent of Britain's and America's concession and inducement policies was to strengthen reformers or moderates in the political leadership or wings of power who were engaged in leadership struggles with hard-liners, and concomitantly to increase the size of their domestic base of support.

By strengthening their power and position, London and Washington sought to assist in realigning the foreign policies of these countries away from massive rearmament, extreme autarky and war preparation -- or at least to slow them down and to buy time for moderate-paced rearmament.

There are four lessons that the Obama administration can learn from Britain's and America's policies of engagement. First, there is the danger of believing that moderates in the wings of power and their domestic supporters are strong enough to curb the extreme policies of the hard-liners. The Obama administration will find that hard-liners in Iran, especially the Revolutionary Guard, are significantly stronger than the moderates.

Second, there is the constant danger of domestic obstructionist politics in blocking concessions. Obama will require the support of Congress to roll back sanctions and the Senate to ratify any changes to treaties. Moreover, as Charles Kupchan notes, it is possible that the Jackson-Vanik amendment, which is still on the books, could once again re-emerge to trip up another president's plans of engaging the enemy.

Third, competing elements of foreign policy can work at cross purposes and thereby weaken rather than strengthen foreign moderates. Specifically, pressure on China to revalue its currency could undermine the power and position of the moderate-internationalist bloc or push them into the hard-line nationalist camp.

Finally, a strategy of concessions is most likely to succeed if the boost reshuffles the balance of domestic political power and if the political institutions in the target state grant privileged access to moderate internationalists. This is most likely to occur in states with a growing internationalist bloc of political leaders that are committed to internationalization.

Steven E. Lobell is associate professor in the University of Utah Department of Political Science.