CAMBRIDGE – More than 130,000 people are said to have died in Syria’s civil war. United Nations reports of atrocities, Internet images of attacks on civilians, and accounts of suffering refugees rend our hearts. But what is to be done – and by whom?

Recently, the Canadian scholar-politician Michael Ignatieff urged US President Barack Obama to impose a no-fly zone over Syria, despite the near-certainty that Russia would veto the United Nations Security Council resolution needed to legalize such a move. In Ignatieff’s view, if Syrian President Bashar al-Assad is allowed to prevail, his forces will obliterate the remaining Sunni insurgents – at least for now; with hatreds inflamed, blood eventually will flow again.

In an adjoining article, the columnist Thomas Friedman drew some lessons from the United States’ recent experience in the Middle East. First, Americans understand little about the social and political complexities of the countries there. Second, the US can stop bad things from happening (at considerable cost), but it cannot make good things happen by itself. And, third, when America tries to make good things happen in these countries, it runs the risk of assuming responsibility for solving their problems.

So what are a leader’s duties beyond borders? The problem extends far beyond Syria – witness recent killings in South Sudan, the Central African Republic, Somalia, and other places. In 2005, the UN General Assembly unanimously recognized a “responsibility to protect” citizens when their own government fails to do so, and in 2011 it was invoked in UN Security Council Resolution 1973, authorizing the use of military force in Libya.

Russia, China, and others believe that the principle was misused in Libya, and that the guiding doctrine of international law remains the UN Charter, which prohibits the use of force except in self-defense, or when authorized by the Security Council. But, back in 1999, when faced with a Russian veto of a potential Security Council resolution in the case of Kosovo, NATO used force anyway, and many defenders argued that, legality aside, the decision was morally justified.

So which arguments should political leaders follow when trying to decide the right policy to pursue? The answer depends, in part, on the collectivity to which he or she feels morally obliged.

Above the small-group level, human identity is shaped by what Benedict Anderson calls “imagined communities.” Few people have direct experience of the other members of the community with which they identify. In recent centuries, the nation has been the imagined community for which most people were willing to make sacrifices, and even to die, and most leaders have seen their primary obligations to be national in scope.

In a world of globalization, however, many people belong to multiple imagined communities. Some – local, regional, national, cosmopolitan – seem to be arranged as concentric circles, with the strength of identity diminishing with distance from the core; but, in a global information age, this ordering has become confused.

Today, many identities are overlapping circles – affinities sustained by the Internet and cheap travel. Diasporas are now a mouse click away. Professional groups adhere to transnational standards. Activist groups, ranging from environmentalists to terrorists, also connect across borders.

As a result, sovereignty is no longer as absolute and impenetrable as it once seemed. This is the reality that the UN General Assembly acknowledged when it recognized a responsibility to protect endangered people in sovereign states.

But what moral obligation does this place on a particular leader like Obama? The leadership theorist Barbara Kellerman has accused former US President Bill Clinton of the moral failure of insularity for his inadequate response to the genocide in Rwanda in 1994. In one sense, she is right. But other leaders were also insular, and no country responded adequately.

Had Clinton tried to send American troops, he would have encountered stiff resistance in the US Congress. Coming so soon after the death of US soldiers in the 1993 humanitarian intervention in Somalia, the American public was in no mood for another military mission abroad.

So what should a democratically elected leader do in such circumstances? Clinton has acknowledged that he could have done more to galvanize the UN and other countries to save lives in Rwanda. But good leaders today are often caught between their personal cosmopolitan inclinations and their more traditional obligations to the citizens who elected them.

Fortunately, insularity is not an “all or nothing” moral proposition. In a world in which people are organized in national communities, a purely cosmopolitan ideal is unrealistic. Global income equalization, for example, is not a credible obligation for a national political leader; but such a leader could rally followers by saying that more should be done to reduce poverty and disease worldwide.

As the philosopher Kwame Anthony Appiah has put it, “Thou shalt not kill is a test you take pass-fail. Honor thy father and thy mother admits of gradations.”

The same is true of cosmopolitanism versus insularity. We may admire leaders who make efforts to increase their followers’ sense of moral duties beyond borders; but it does little good to hold leaders to an impossible standard that would undercut their capacity to remain leaders.

As Obama wrestles with determining his responsibilities in Syria and elsewhere, he faces a serious moral dilemma. As Appiah says, duties beyond borders are a matter of degree; and there are also degrees of intervention that range from aid to refugees and arms to different degrees of the use of force.

But even when making these graduated choices, a leader also owes his followers a duty of prudence – of remembering the Hippocratic oath to first of all, do no harm. Ignatieff says Obama already owns the consequences of his inaction; Friedman reminds him of the virtue of prudence. Pity Obama.

Copyright Project Syndicate

Joseph S. Nye, Jr. is a professor at Harvard and author of Presidential Leadership and the Creation of the American Era.

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