Lean Forward

Since the end of World War II, the United States has pursued a single grand strategy: deep engagement. In an effort to protect its security and prosperity, the country has promoted a liberal economic order and established close defense ties with partners in Europe, East Asia, and the Middle East. Its military bases cover the map, its ships patrol transit routes across the globe, and tens of thousands of its troops stand guard in allied countries such as Germany, Japan, and South Korea.

The details of U.S. foreign policy have differed from administration to administration, including the emphasis placed on democracy promotion and humanitarian goals, but for over 60 years, every president has agreed on the fundamental decision to remain deeply engaged in the world, even as the rationale for that strategy has shifted. During the Cold War, the United States' security commitments to Europe, East Asia, and the Middle East served primarily to prevent Soviet encroachment into the world's wealthiest and most resource-rich regions. Since the fall of the Soviet Union, the aim has become to make these same regions more secure, and thus less threatening to the United States, and to use these security partnerships to foster the cooperation necessary for a stable and open international order.

Now, more than ever, Washington might be tempted to abandon this grand strategy and pull back from the world. The rise of China is chipping away at the United States' preponderance of power, a budget crisis has put defense spending on the chopping block, and two long wars have left the U.S. military and public exhausted. Indeed, even as most politicians continue to assert their commitment to global leadership, a very different view has taken hold among scholars of international relations over the past decade: that the United States should minimize its overseas military presence, shed its security ties, and give up its efforts to lead the liberal international order.

Proponents of retrenchment argue that a globally engaged grand strategy wastes money by subsidizing the defense of well-off allies and generates resentment among foreign populations and governments. A more modest posture, they contend, would put an end to allies' free-riding and defuse anti-American sentiment. Even if allies did not take over every mission the United States now performs, most of these roles have nothing to do with U.S. security and only risk entrapping the United States in unnecessary wars. In short, those in this camp maintain that pulling back would not only save blood and treasure but also make the United States more secure.

They are wrong. In making their case, advocates of retrenchment overstate the costs of the current grand strategy and understate its benefits. In fact, the budgetary savings of lowering the United States' international profile are debatable, and there is little evidence to suggest that an internationally engaged America provokes other countries to balance against it, becomes overextended, or gets dragged into unnecessary wars.

The benefits of deep engagement, on the other hand, are legion. U.S. security commitments reduce competition in key regions and act as a check against potential rivals. They help maintain an open world economy and give Washington leverage in economic negotiations. And they make it easier for the United States to secure cooperation for combating a wide range of global threats. Were the United States to cede its global leadership role, it would forgo these proven upsides while exposing itself to the unprecedented downsides of a world in which the country was less secure, prosperous, and influential.

AN AFFORDABLE STRATEGY

Many advocates of retrenchment consider the United States' assertive global posture simply too expensive. The international relations scholar Christopher Layne, for example, has warned of the country's "ballooning budget deficits" and argued that "its strategic commitments exceed the resources available to support them." Calculating the savings of switching grand strategies, however, is not so simple, because it depends on the expenditures the current strategy demands and the amount required for its replacement -- numbers that are hard to pin down.

If the United States revoked all its security guarantees, brought home all its troops, shrank every branch of the military, and slashed its nuclear arsenal, it would save around $900 billion over ten years, according to Benjamin Friedman and Justin Logan of the Cato Institute. But few advocates of retrenchment endorse such a radical reduction; instead, most call for "restraint," an "offshore balancing" strategy, or an "over the horizon" military posture. The savings these approaches would yield are less clear, since they depend on which security commitments Washington would abandon outright and how much it would cost to keep the remaining ones. If retrenchment simply meant shipping foreign-based U.S. forces back to the United States, then the savings would be modest at best, since the countries hosting U.S. forces usually cover a large portion of the basing costs. And if it meant maintaining a major expeditionary capacity, then any savings would again be small, since the Pentagon would still have to pay for the expensive weaponry and equipment required for projecting power abroad.

The other side of the cost equation, the price of continued engagement, is also in flux. Although the fat defense budgets of the past decade make an easy target for advocates of retrenchment, such high levels of spending aren't needed to maintain an engaged global posture. Spending skyrocketed after 9/11, but it has already begun to fall back to earth as the United States winds down its two costly wars and trims its base level of nonwar spending. As of the fall of 2012, the Defense Department was planning for cuts of just under $500 billion over the next five years, which it maintains will not compromise national security. These reductions would lower military spending to a little less than three percent of GDP by 2017, from its current level of 4.5 percent. The Pentagon could save even more with no ill effects by reforming its procurement practices and compensation policies.

Even without major budget cuts, however, the country can afford the costs of its ambitious grand strategy. The significant increases in military spending proposed by Mitt Romney, the Republican candidate, during the 2012 presidential campaign would still have kept military spending below its current share of GDP, since spending on the wars in Afghanistan and Iraq would still have gone down and Romney's proposed nonwar spending levels would not have kept pace with economic growth. Small wonder, then, that the case for pulling back rests more on the nonmonetary costs that the current strategy supposedly incurs.

UNBALANCED

One such alleged cost of the current grand strategy is that, in the words of the political scientist Barry Posen, it "prompts states to balance against U.S. power however they can." Yet there is no evidence that countries have banded together in anti-American alliances or tried to match the United States' military capacity on their own -- or that they will do so in the future.

Indeed, it's hard to see how the current grand strategy could generate true counterbalancing. Unlike past hegemons, the United States is geographically isolated, which means that it is far less threatening to other major states and that it faces no contiguous great-power rivals that could step up to the task of balancing against it. Moreover, any competitor would have a hard time matching the U.S. military. Not only is the United States so far ahead militarily in both quantitative and qualitative terms, but its security guarantees also give it the leverage to prevent allies from giving military technology to potential U.S. rivals. Because the United States dominates the high-end defense industry, it can trade access to its defense market for allies' agreement not to transfer key military technologies to its competitors. The embargo that the United States has convinced the EU to maintain on military sales to China since 1989 is a case in point.

If U.S. global leadership were prompting balancing, then one would expect actual examples of pushback -- especially during the administration of George W. Bush, who pursued a foreign policy that seemed particularly unilateral. Yet since the Soviet Union collapsed, no major powers have tried to balance against the United States by seeking to match its military might or by assembling a formidable alliance; the prospect is simply too daunting. Instead, they have resorted to what scholars call "soft balancing," using international institutions and norms to constrain Washington. Setting aside the fact that soft balancing is a slippery concept and difficult to distinguish from everyday diplomatic competition, it is wrong to say that the practice only harms the United States. Arguably, as the global leader, the United States benefits from employing soft-balancing-style leverage more than any other country. After all, today's rules and institutions came about under its auspices and largely reflect its interests, and so they are in fact tailor-made for soft balancing by the United States itself. In 2011, for example, Washington coordinated action with several Southeast Asian states to oppose Beijing's claims in the South China Sea by pointing to established international law and norms.

Another argument for retrenchment holds that the United States will fall prey to the same fate as past hegemons and accelerate its own decline. In order to keep its ambitious strategy in place, the logic goes, the country will have to divert resources away from more productive purposes -- infrastructure, education, scientific research, and so on -- that are necessary to keep its economy competitive. Allies, meanwhile, can get away with lower military expenditures and grow faster than they otherwise would.

The historical evidence for this phenomenon is thin; for the most part, past superpowers lost their leadership not because they pursued hegemony but because other major powers balanced against them -- a prospect that is not in the cards today. (If anything, leading states can use their position to stave off their decline.) A bigger problem with the warnings against "imperial overstretch" is that there is no reason to believe that the pursuit of global leadership saps economic growth. Instead, most studies by economists find no clear relationship between military expenditures and economic decline.

To be sure, if the United States were a dramatic outlier and spent around a quarter of its GDP on defense, as the Soviet Union did in its last decades, its growth and competitiveness would suffer. But in 2012, even as it fought a war in Afghanistan and conducted counterterrorism operations around the globe, Washington spent just 4.5 percent of GDP on defense -- a relatively small fraction, historically speaking. (From 1950 to 1990, that figure averaged 7.6 percent.) Recent economic difficulties might prompt Washington to reevaluate its defense budgets and international commitments, but that does not mean that those policies caused the downturn. And any money freed up from dropping global commitments would not necessarily be spent in ways that would help the U.S. economy.

Likewise, U.S. allies' economic growth rates have nothing to do with any security subsidies they receive from Washington. The contention that lower military expenditures facilitated the rise of Japan, West Germany, and other countries dependent on U.S. defense guarantees may have seemed plausible during the last bout of declinist anxiety, in the 1980s. But these states eventually stopped climbing up the global economic ranks as their per capita wealth approached U.S. levels -- just as standard models of economic growth would predict. Over the past 20 years, the United States has maintained its lead in per capita GDP over its European allies and Japan, even as those countries' defense efforts have fallen further behind. Their failure to modernize their militaries has only served to entrench the United States' dominance.

LED NOT INTO TEMPTATION

The costs of U.S. foreign policy that matter most, of course, are human lives, and critics of an expansive grand strategy worry that the United States might get dragged into unnecessary wars. Securing smaller allies, they argue, emboldens those states to take risks they would not otherwise accept, pulling the superpower sponsor into costly conflicts -- a classic moral hazard problem. Concerned about the reputational costs of failing to honor the country's alliance commitments, U.S. leaders might go to war even when no national interests are at stake.

History shows, however, that great powers anticipate the danger of entrapment and structure their agreements to protect themselves from it. It is nearly impossible to find a clear case of a smaller power luring a reluctant great power into war. For decades, World War I served as the canonical example of entangling alliances supposedly drawing great powers into a fight, but an outpouring of new historical research has overturned the conventional wisdom, revealing that the war was more the result of a conscious decision on Germany's part to try to dominate Europe than a case of alliance entrapment.

If anything, alliances reduce the risk of getting pulled into a conflict. In East Asia, the regional security agreements that Washington struck after World War II were designed, in the words of the political scientist Victor Cha, to "constrain anticommunist allies in the region that might engage in aggressive behavior against adversaries that could entrap the United States in an unwanted larger war." The same logic is now at play in the U.S.-Taiwanese relationship. After cross-strait tensions flared in the 1990s and the first decade of this century, U.S. officials grew concerned that their ambiguous support for Taiwan might expose them to the risk of entrapment. So the Bush administration adjusted its policy, clarifying that its goal was to not only deter China from an unprovoked attack but also deter Taiwan from unilateral moves toward independence.

For many advocates of retrenchment, the problem is that the mere possession of globe-girdling military capabilities supposedly inflates policymakers' conception of the national interest, so much so that every foreign problem begins to look like America's to solve. Critics also argue that the country's military superiority causes it to seek total solutions to security problems, as in Afghanistan and Iraq, that could be dealt with in less costly ways. Only a country that possessed such awesome military power and faced no serious geopolitical rival would fail to be satisfied with partial fixes, such as containment, and instead embark on wild schemes of democracy building, the argument goes.

Furthermore, they contend, the United States' outsized military creates a sense of obligation to do something with it even when no U.S. interests are at stake. As Madeleine Albright, then the U.S. ambassador to the un, famously asked Colin Powell, then chairman of the Joint Chiefs of Staff, when debating intervention in Bosnia in 1993, "What's the point of having this superb military you're always talking about if we can't use it?"

If the U.S. military scrapped its forces and shuttered its bases, then the country would no doubt eliminate the risk of entering needless wars, having tied itself to the mast like Ulysses. But if it instead merely moved its forces over the horizon, as is more commonly proposed by advocates of retrenchment, whatever temptations there were to intervene would not disappear. The bigger problem with the idea that a forward posture distorts conceptions of the national interest, however, is that it rests on just one case: Iraq. That war is an outlier in terms of both its high costs (it accounts for some two-thirds of the casualties and budget costs of all U.S. wars since 1990) and the degree to which the United States shouldered them alone. In the Persian Gulf War and the interventions in Bosnia, Kosovo, Afghanistan, and Libya, U.S. allies bore more of the burden, controlling for the size of their economies and populations.

Besides, the Iraq war was not an inevitable consequence of pursuing the United States' existing grand strategy; many scholars and policymakers who prefer an engaged America strongly opposed the war. Likewise, continuing the current grand strategy in no way condemns the United States to more wars like it. Consider how the country, after it lost in Vietnam, waged the rest of the Cold War with proxies and highly limited interventions. Iraq has generated a similar reluctance to undertake large expeditionary operations -- what the political scientist John Mueller has dubbed "the Iraq syndrome." Those contending that the United States' grand strategy ineluctably leads the country into temptation need to present much more evidence before their case can be convincing.

KEEPING THE PEACE

Of course, even if it is true that the costs of deep engagement fall far below what advocates of retrenchment claim, they would not be worth bearing unless they yielded greater benefits. In fact, they do. The most obvious benefit of the current strategy is that it reduces the risk of a dangerous conflict. The United States' security commitments deter states with aspirations to regional hegemony from contemplating expansion and dissuade U.S. partners from trying to solve security problems on their own in ways that would end up threatening other states.

Skeptics discount this benefit by arguing that U.S. security guarantees aren't necessary to prevent dangerous rivalries from erupting. They maintain that the high costs of territorial conquest and the many tools countries can use to signal their benign intentions are enough to prevent conflict. In other words, major powers could peacefully manage regional multipolarity without the American pacifier.

But that outlook is too sanguine. If Washington got out of East Asia, Japan and South Korea would likely expand their military capabilities and go nuclear, which could provoke a destabilizing reaction from China. It's worth noting that during the Cold War, both South Korea and Taiwan tried to obtain nuclear weapons; the only thing that stopped them was the United States, which used its security commitments to restrain their nuclear temptations. Similarly, were the United States to leave the Middle East, the countries currently backed by Washington -- notably, Israel, Egypt, and Saudi Arabia -- might act in ways that would intensify the region's security dilemmas.

There would even be reason to worry about Europe. Although it's hard to imagine the return of great-power military competition in a post-American Europe, it's not difficult to foresee governments there refusing to pay the budgetary costs of higher military outlays and the political costs of increasing EU defense cooperation. The result might be a continent incapable of securing itself from threats on its periphery, unable to join foreign interventions on which U.S. leaders might want European help, and vulnerable to the influence of outside rising powers.

Given how easily a U.S. withdrawal from key regions could lead to dangerous competition, advocates of retrenchment tend to put forth another argument: that such rivalries wouldn't actually hurt the United States. To be sure, few doubt that the United States could survive the return of conflict among powers in Asia or the Middle East -- but at what cost? Were states in one or both of these regions to start competing against one another, they would likely boost their military budgets, arm client states, and perhaps even start regional proxy wars, all of which should concern the United States, in part because its lead in military capabilities would narrow.

Greater regional insecurity could also produce cascades of nuclear proliferation as powers such as Egypt, Saudi Arabia, Japan, South Korea, and Taiwan built nuclear forces of their own. Those countries' regional competitors might then also seek nuclear arsenals. Although nuclear deterrence can promote stability between two states with the kinds of nuclear forces that the Soviet Union and the United States possessed, things get shakier when there are multiple nuclear rivals with less robust arsenals. As the number of nuclear powers increases, the probability of illicit transfers, irrational decisions, accidents, and unforeseen crises goes up.

The case for abandoning the United States' global role misses the underlying security logic of the current approach. By reassuring allies and actively managing regional relations, Washington dampens competition in the world's key areas, thereby preventing the emergence of a hothouse in which countries would grow new military capabilities. For proof that this strategy is working, one need look no further than the defense budgets of the current great powers: on average, since 1991 they have kept their military expenditures as a percentage of GDP to historic lows, and they have not attempted to match the United States' top-end military capabilities. Moreover, all of the world's most modern militaries are U.S. allies, and the United States' military lead over its potential rivals is by many measures growing.

On top of all this, the current grand strategy acts as a hedge against the emergence regional hegemons. Some supporters of retrenchment argue that the U.S. military should keep its forces over the horizon and pass the buck to local powers to do the dangerous work of counterbalancing rising regional powers. Washington, they contend, should deploy forces abroad only when a truly credible contender for regional hegemony arises, as in the cases of Germany and Japan during World War II and the Soviet Union during the Cold War. Yet there is already a potential contender for regional hegemony -- China -- and to balance it, the United States will need to maintain its key alliances in Asia and the military capacity to intervene there. The implication is that the United States should get out of Afghanistan and Iraq, reduce its military presence in Europe, and pivot to Asia. Yet that is exactly what the Obama administration is doing.

MILITARY DOMINANCE, ECONOMIC PREEMINENCE

Preoccupied with security issues, critics of the current grand strategy miss one of its most important benefits: sustaining an open global economy and a favorable place for the United States within it. To be sure, the sheer size of its output would guarantee the United States a major role in the global economy whatever grand strategy it adopted. Yet the country's military dominance undergirds its economic leadership. In addition to protecting the world economy from instability, its military commitments and naval superiority help secure the sea-lanes and other shipping corridors that allow trade to flow freely and cheaply. Were the United States to pull back from the world, the task of securing the global commons would get much harder. Washington would have less leverage with which it could convince countries to cooperate on economic matters and less access to the military bases throughout the world needed to keep the seas open.

A global role also lets the United States structure the world economy in ways that serve its particular economic interests. During the Cold War, Washington used its overseas security commitments to get allies to embrace the economic policies it preferred -- convincing West Germany in the 1960s, for example, to take costly steps to support the U.S. dollar as a reserve currency. U.S. defense agreements work the same way today. For example, when negotiating the 2011 free-trade agreement with South Korea, U.S. officials took advantage of Seoul's desire to use the agreement as a means of tightening its security relations with Washington. As one diplomat explained to us privately, "We asked for changes in labor and environment clauses, in auto clauses, and the Koreans took it all." Why? Because they feared a failed agreement would be "a setback to the political and security relationship."

More broadly, the United States wields its security leverage to shape the overall structure of the global economy. Much of what the United States wants from the economic order is more of the same: for instance, it likes the current structure of the World Trade Organization and the International Monetary Fund and prefers that free trade continue. Washington wins when U.S. allies favor this status quo, and one reason they are inclined to support the existing system is because they value their military alliances. Japan, to name one example, has shown interest in the Trans-Pacific Partnership, the Obama administration's most important free-trade initiative in the region, less because its economic interests compel it to do so than because Prime Minister Yoshihiko Noda believes that his support will strengthen Japan's security ties with the United States.

The United States' geopolitical dominance also helps keep the U.S. dollar in place as the world's reserve currency, which confers enormous benefits on the country, such as a greater ability to borrow money. This is perhaps clearest with Europe: the EU's dependence on the United States for its security precludes the EU from having the kind of political leverage to support the euro that the United States has with the dollar. As with other aspects of the global economy, the United States does not provide its leadership for free: it extracts disproportionate gains. Shirking that responsibility would place those benefits at risk.

CREATING COOPERATION

What goes for the global economy goes for other forms of international cooperation. Here, too, American leadership benefits many countries but disproportionately helps the United States. In order to counter transnational threats, such as terrorism, piracy, organized crime, climate change, and pandemics, states have to work together and take collective action. But cooperation does not come about effortlessly, especially when national interests diverge. The United States' military efforts to promote stability and its broader leadership make it easier for Washington to launch joint initiatives and shape them in ways that reflect U.S. interests. After all, cooperation is hard to come by in regions where chaos reigns, and it flourishes where leaders can anticipate lasting stability.

U.S. alliances are about security first, but they also provide the political framework and channels of communication for cooperation on nonmilitary issues. NATO, for example, has spawned new institutions, such as the Atlantic Council, a think tank, that make it easier for Americans and Europeans to talk to one another and do business. Likewise, consultations with allies in East Asia spill over into other policy issues; for example, when American diplomats travel to Seoul to manage the military alliance, they also end up discussing the Trans-Pacific Partnership. Thanks to conduits such as this, the United States can use bargaining chips in one issue area to make progress in others.

The benefits of these communication channels are especially pronounced when it comes to fighting the kinds of threats that require new forms of cooperation, such as terrorism and pandemics. With its alliance system in place, the United States is in a stronger position than it would otherwise be to advance cooperation and share burdens. For example, the intelligence-sharing network within NATO, which was originally designed to gather information on the Soviet Union, has been adapted to deal with terrorism. Similarly, after a tsunami in the Indian Ocean devastated surrounding countries in 2004, Washington had a much easier time orchestrating a fast humanitarian response with Australia, India, and Japan, since their militaries were already comfortable working with one another. The operation did wonders for the United States' image in the region.

The United States' global role also has the more direct effect of facilitating the bargains among governments that get cooperation going in the first place. As the scholar Joseph Nye has written, "The American military role in deterring threats to allies, or of assuring access to a crucial resource such as oil in the Persian Gulf, means that the provision of protective force can be used in bargaining situations.  Sometimes the linkage may be direct; more often it is a factor not mentioned openly but present in the back of statesmen's minds."

THE DEVIL WE KNOW

Should America come home? For many prominent scholars of international relations, the answer is yes -- a view that seems even wiser in the wake of the disaster in Iraq and the Great Recession. Yet their arguments simply don't hold up. There is little evidence that the United States would save much money switching to a smaller global posture. Nor is the current strategy self-defeating: it has not provoked the formation of counterbalancing coalitions or caused the country to spend itself into economic decline. Nor will it condemn the United States to foolhardy wars in the future. What the strategy does do is help prevent the outbreak of conflict in the world's most important regions, keep the global economy humming, and make international cooperation easier. Charting a different course would threaten all these benefits.

This is not to say that the United States' current foreign policy can't be adapted to new circumstances and challenges. Washington does not need to retain every commitment at all costs, and there is nothing wrong with rejiggering its strategy in response to new opportunities or setbacks. That is what the Nixon administration did by winding down the Vietnam War and increasing the United States' reliance on regional partners to contain Soviet power, and it is what the Obama administration has been doing after the Iraq war by pivoting to Asia. These episodes of rebalancing belie the argument that a powerful and internationally engaged America cannot tailor its policies to a changing world.

A grand strategy of actively managing global security and promoting the liberal economic order has served the United States exceptionally well for the past six decades, and there is no reason to give it up now. The country's globe-spanning posture is the devil we know, and a world with a disengaged America is the devil we don't know. Were American leaders to choose retrenchment, they would in essence be running a massive experiment to test how the world would work without an engaged and liberal leading power. The results could well be disastrous.