Alexander Downes concludes, “The record of foreign-imposed regime change over the past two centuries is not a happy one. . . . . It is important to reserve the extreme option of regime change—as opposed to less intrusive forms of intervention—for real disasters.” But there are exceptions to Downes’s rule, as he acknowledges. At the high end of the spectrum of conflict, regime change in Germany and Japan after World War II served essential American interests, and at the low end, regime change in the small West African countries of Sierra Leone and Liberia in the 1990s fostered important humanitarian improvements. How then should we decide when to act?

As I argue in The Future of Power, a smart strategy provides the answers to five questions. First, what are our objectives? The answer means setting priorities that will structure tradeoffs. What do we want from a specific case of regime change, and how does pursuing that end affect our other objectives? Second, we need not only an accurate and complete inventory of power resources, but an understanding of when they will (or will not) be available to accomplish regime change. Third, a smart strategy asks about the positions and preferences of the targets of regime change. What are those preferences, how intensely are they held, and how can they be changed? That leads to the fourth question: which forms of power are most likely to succeed in a reasonably quick and cost-effective way? Are we more likely to succeed with hard military power or with the soft power of agenda setting, persuasion, and attraction? Or is the best option a combination of hard and soft?

Finally, what is the probability of success? Noble causes can have terrible consequences if they are accompanied by excessive optimism. For example, no matter the objectives of the American invasion of Iraq, the initiation of war was accompanied by what proved to be hubristic blindness about the eventual time and costs involved. It is worth remembering that the ancient tradition of just war theory asks not only about proportionality and civilian casualties, but also how the probability of success will affect consequences. If the probability of success is too low, one should return to the first question and reassess goals and priorities.

In Libya, Obama has balanced interests and values while limiting risks.

In the case of Libya, President Obama showed awareness of these questions in ways that his more interventionist critics did not. First he was careful to limit both objectives and commitments. Humanitarian interests are important but not vital to national survival. Moreover, there is always a danger of good intentions leading to unintended bad consequences, as happened in Somalia in 1992–93. Thus while Obama correctly said that the United States wanted to see Qaddafi overthrown, he made clear that another party would have to be responsible. Second, Obama was careful not to create a global narrative of a third American military attack on a Muslim country, which would have reverberated from Morocco to Indonesia. Instead he waited until Arab League and UN Security Council resolutions provided a narrative that stressed the legitimate enforcement of a humanitarian responsibility to protect civilians. Third, he encouraged France, Britain, and other allies to share in the lead, and also encouraged NATO, a multilateral institution, to take charge of the no-fly zone.

The outcome in Libya was and remains uncertain. Qaddafi might fall because of further defections, but the fighting between his forces and the resistance could also lead to a stalemated civil war. If so, Obama established a basis for avoiding ownership of a nasty problem. Some foreign-policy realists question Obama’s decision to be involved in a humanitarian action based on what is known as the “responsibility to protect,” but in terms of balancing interests and values while limiting risks, Obama provided a lesson in smart leadership.

American goals in the 21st century should not be about preserving hegemony. Our task now is to combine resources into successful strategies in the new context of power diffusion and the “rise of the rest.” As the most powerful country, the United States remains the most important leader in global affairs, but the twentieth-century account of American hegemony is misleading. The choices we face are not between isolationism and frequent interventions to force regime change. They are about prudent strategy. In this regard, Downes furnishes good advice.