Whenever there’s a conflict anywhere in the world, a gaggle of American pundits and politicians insists that the United States fix it. Whether it's Senators John McCain and Lindsey Graham pushing weapons shipments to Ukraine, former ambassador Robert Ford urging Washington to arm Syrian rebels, or The Weekly Standard’s Bill Kristol calling for troops to be sent to Iraq, the assumption is always that every problem is America's problem, and that the best way to solve America's problems is with force.
Barry Posen, a professor of political science at MIT and a foreign-policy realist, advocates a different approach. The title of his new book, Restraint, succinctly expresses his policy recommendation. The U.S., he argues, needs to stop trying to do more and more. Instead, it needs to do less. Or, as he puts it, "Efforts to defend everything leave one defending not much of anything."
Posen rests his discussion on two basic arguments. The first is that the United States is, by any reasonable metric, an incredibly secure nation. It is geographically isolated from other great powers—a position that makes invading or even attacking the U.S. mainland prohibitively difficult. U.S. conventional forces are by far the most powerful in the world. Posen notes that the U.S. "accounted for a little more than a third of all the military spending in the world during the 1990s," and has increased the percentage to about 41 percent of all military spending in the world today. On top of that, the U.S. has a massive nuclear deterrent. It is simply not credible to argue that Iran, North Korea, Iraq, Pakistan, or even Russia or China have the combination of dangerous capabilities and malign intentions to pose a serious existential threat to the United States in anything but the most paranoid neocon fantasies.
Second, enforcing “liberal hegemony”—a grand strategy of promoting global democracy and peace underwritten by U.S. military power—is simply beyond America’s capabilities. As the wars in Iraq, Afghanistan, and, earlier, Vietnam showed, the United States does not have the military resources and political will necessary to impose friendly democratic regimes upon distant peoples. Nor, as all three of those wars also demonstrate, does it have the ability to utterly destroy its enemies forever. Nor, finally, can the U.S. ensure, militarily or otherwise, that no one anywhere gets nuclear weapons—after all, if it could, presumably Pakistan and North Korea wouldn't have them.
The effort to control and police the world through force of arms makes the United States less secure in numerous ways, Posen argues. It bleeds U.S. resources, both military and economic, while leaving the country less prepared to face immediate threats. The belief that America will act as the world’s policeman encourages some of its allies to skimp on their own defense spending, forcing the U.S. to undertake further costly investments it cannot afford in the long term. In its role as Liberal Hegemon, it also encourages aggression and risky behavior in states like Israel, which can put off peace deals and engage in provocative actions like settlement construction because of the elaborate pledges of support it has received from America.
Rather than imposing American will by force, Posen suggests that we could more fruitfully and practically engage the world in other ways. For instance, if the U.S. is concerned about genocide, we could join the International Criminal Court and support the prosecution of those who commit war crimes (including, though Posen does not say this, American officials, at whatever level, who condoned, or condone, torture.) If we want to save people, we could honor our commitments under international treaties and open our borders to refugees; as Posen says, we are “rich enough to receive many individuals in such dire straits.” We could also send aid to poorer countries to encourage them to receive refugees.
Posen makes a compelling argument. But he makes it almost entirely on realist grounds. He advocates a policy of restraint because it will make the U.S. stronger and more secure, not—or at least not primarily—because a policy of restraint is more ethical than the alternative. His humanitarian suggestions—joining the ICC, opening borders—are addendums to, rather than the essence of, his reasoning.
But liberal hegemony, the argument Posen is rebutting, isn’t just based on security interests. It’s also predicated on morality. For instance, the rationale for invading Iraq was not only that the United States needed to crush Saddam Hussein for its own safety. It was also that Saddam was uniquely evil and that it would be good for the people of Iraq, and for people around the world, if he were destroyed. Similarly, the continuing presence of U.S. troops in Afghanistan is justified not only on the basis of protecting America from al-Qaeda, but also on the grounds that the Taliban are hideously oppressive, especially to women, and that it is America’s responsibility to stop them from returning to power.
Responding to the argument for liberal hegemony, then, requires consideration of the moral as well as the practical arguments for restraint. Fortunately for Posen, the “just war” tradition of ethics yields a very strong argument for the morality of restraint—indeed, in many ways just-war doctrine is based on the restraint principle. As summarized by the Internet Encyclopedia of Philosophy:
The principles of the justice of war are commonly held to be: having just cause, being a last resort, being declared by a proper authority, possessing right intention, having a reasonable chance of success, and the end being proportional to the means used.
The just-war doctrine is not equivalent to pacifism, which holds that there is no justification for war at all. But it shares with pacifism, as political ethicist Jean Bethke Elshtain has written, the belief that "violence must never be celebrated, and that violence must always be put on trial." Though Elshtain herself supported the Iraq war, the reasoning here suggests, on the contrary, that preventive wars aimed at warding off the eventual emergence of a threat should be anathema. Wars are by their nature bloody, destructive, and impossible to control (as the spiraling and ongoing violence in Iraq demonstrates all too clearly.) It is simply not tenable to argue that starting a war will preserve peace, because war by its nature breeds chaos and more war. That's why war must be a last resort, and why it should solely be used in self-defense; the only time it's reasonable to think that war might reduce war is when you're already at war.
The essence of just war can be summarized generally as follows: first, try to limit harm, and second, treat war with respect and fear. Dropping bombs on Libya or Iran to prevent evil is illegitimate because war itself is evil—and it is an evil not easily contained. Treating war as a convenient tool of policy, rather than as a last resort, sows more death and hardship, not less. Similarly, building up massive stockpiles of weapons that are not immediately necessary creates a temptation to use those weapons—the succinct moral of Johnny Cash's "Don't Take Your Guns to Town." Outsized military expenditures can themselves be seen as a violation of the principles that inform the just-war doctrine.
From the just-war perspective, Posen's realist arguments have an ethical force. Even from the perspective of the World War II-era realist theologian Reinhold Niebuhr, who rejected pacifism and just war alike as overly idealistic, Posen's position has moral consequences. Niebuhr saw war as moral when it advanced best outcomes. The case Posen outlines suggests what those best outcomes are.
When Posen says, for example, that the U.S. cannot, in the long run, defend Taiwan, that's not just a practical statement, but an ethical one. That’s because engaging in an unwinnable conflict over Taiwan—possibly unleashing nuclear war in a lost cause without a self-defense rationale—is, on just-war grounds, or even on Neibuhrian grounds, morally wrong. Similarly, there is plentiful evidence that the U.S. cannot impose its preferred form of government on the peoples of the Middle East. Intervening in Middle Eastern civil wars when there is no realistic chance of success is an ethical failure as well as a tactical one. It is evil to bomb people purely in the hope, against all the evidence, that bombing will make things better.
Restraint is also preferable to liberal hegemony from the standpoint of American ideals. Proponents of liberal hegemony often argue that the United States has an ethical duty to spread its values across the globe. But this argument overlooks the fact that one of the most basic foundational values of America is self-determination. The American Revolution was fought for the principle that people have a right to make decisions about their own fate through their own institutions. When the U.S. sets itself up as a global policeman, it is saying, on the contrary, that U.S. policymakers have the right to decide who should rule in Iraq, or how Iran should conduct its nuclear program. Perhaps, in certain cases, for the security of its own citizens, the U.S. may need to take steps to curtail the actions of other states and other people. But as a wholesale philosophy, "the United States should run the world" contradicts America’s most basic value: that people have the right to rule themselves.
Restraint, then, is not merely a practical necessity for the United States to improve its security. It's also an ethical duty, and a specifically American ideal. Rather than fearing America's "decline" because we’re not able to undertake a land war in Ukraine or a third invasion of Iraq, we should welcome a world in which the U.S. does not try to solve other people's problems by force. Liberal hegemony hasn't worked, and won't work. The United States will be more secure—and more moral—if it can give up its dreams of empire, and restrain its impulse to war.