CAMBRIDGE: This year's presidential campaign in the United States has been marked by calls from Barack Obama's would-be Republican challengers for a radical transformation of American foreign policy. Campaigns are always more extreme than the eventual reality, but countries should be wary of calls for transformational change. Things do not always work out as intended. Foreign policy played almost no role in the 2000 US presidential election. In 2001, George W. Bush started his first term with little interest in foreign policy, but adopted transformational objectives after the September 11, 2001 terrorist attacks. Like Woodrow Wilson, Franklin Roosevelt, and Harry Truman before him, Bush turned to the rhetoric of democracy to rally his followers in a time of crisis. Bill Clinton had also talked about enlarging the role of human rights and democracy in US foreign policy, but most Americans in the 1990's sought normality and a post-Cold War peace dividend rather than change. By contrast, Bush's 2002 National Security Strategy, which came to be called the Bush Doctrine, proclaimed that the US would “identify and eliminate terrorists wherever they are, together with the regimes that sustain them.” The solution to the terrorist problem was to spread democracy everywhere. Bush invaded Iraq ostensibly to remove Saddam Hussein's capacity to use weapons of mass destruction and, in the process, to change the regime. Bush cannot be blamed for the intelligence failures that attributed such weapons to Saddam, given that many other countries shared such estimates. But inadequate understanding of the Iraqi and regional context, together with poor planning and management, undercut Bush's transformational objectives. Although some of Bush's defenders try to credit him with the “Arab Spring” revolutions, the primary Arab participants reject such arguments. Bush was described by The Economist as “obsessed by the idea of being a transformational president; not just a status-quo operator like Bill Clinton.” Then-Secretary of State Condoleezza Rice praised the virtues of “transformational diplomacy.” But, while leadership theorists and editorial writers tend to think that transformational foreign-policy officials are better in either ethics or effectiveness, the evidence does not support this view. Other leadership skills are more important than the usual distinction between transformational and “transactional” leaders. Consider President George H.W. Bush, who did not do “the vision thing,” but whose sound management and execution underpinned one of the most successful US foreign-policy agendas of the past half-century. Perhaps genetic engineers will one day be able to produce leaders equally endowed with both vision and management skills; comparing the two Bushes (who shared half their genes), it is clear that nature has not yet solved the problem. This is not an argument against transformational leaders. Mohandas Gandhi, Nelson Mandela, and Martin Luther King, Jr., played crucial roles in transforming people's identity and aspirations. Nor is this an argument against transformational leaders in US foreign policy. Franklin Roosevelt and Truman made crucial contributions. But, in judging leaders, we need to pay attention to acts of both omission and commission, to what happened and to what was avoided, to the dogs that barked and to those that did not. A big problem in foreign policy is the complexity of the context. We live in a world of diverse cultures, and we know very little about social engineering and how to “build nations.” When we cannot be sure how to improve the world, prudence becomes an important virtue, and grandiose visions can pose grave dangers. In foreign policy, as in medicine, it is important to remember the Hippocratic Oath: first, do no harm. For these reasons, the virtues of transactional leaders with good contextual intelligence are very important. Someone like George H. W. Bush, unable to articulate a vision but able to steer successfully through crises, turns out to be a better leader than someone like his son, possessed of a powerful vision but with little contextual intelligence or management skill. Former Secretary of State George Shultz, who served under Ronald Reagan, once compared his role to gardening — “the constant nurturing of a complex array of actors, interests, and goals.” But Shultz's Stanford colleague, Condoleezza Rice, wanted a more transformational diplomacy that did not accept the world as it was, but tried to change it. As one observer put it, “Rice's ambition is not just to be a gardener — she wants to be a landscape architect.” There is a role for both, depending on the context, but we should avoid the common mistake of automatically thinking that the transformational landscape architect is a better leader than the careful gardener. We should keep this in mind as we assess the current US presidential debates, with their constant reference to American decline. Decline is a misleading metaphor. America is not in absolute decline, and, in relative terms, there is a reasonable probability that it will remain more powerful than any other country in the coming decades. We do not live in a “post-American world,” but we also do not live in the American era of the late 20th century. The US will be faced with a rise in the power resources of many others — both states and non-state actors. It will also confront a growing number of issues that require power with others as much as power over others in order to obtain the country's preferred outcomes. America's capacity to maintain alliances and create cooperative networks will be an important dimension of its hard and soft power. The problem of America's role in the 21st century is not one of (poorly specified) “decline,” but rather of developing the contextual intelligence to understand that even the largest country cannot achieve what it wants without others' help. Educating the public to understand this complex globalized information age, and what is required to operate successfully in it, will be the real transformational leadership task. Thus far, we are not hearing much about it from the Republican candidates. Joseph S. Nye, Jr., a former US assistant secretary of defense, is a professor at Harvard and the author of The Future of Power. This commentary is published by Daily News Egypt in collaboration with Project Syndicate, www.project-syndicate.org.