And then the Soviet empire collapsed, leaving the United States as the sole superpower in a unipolar world. According to former national-security adviser Brent Scowcroft, the United States found itself “standing alone at the height of power. It was, it is, an unparalleled situation in history, one which presents us with the rarest opportunity to shape the world.” And so it tried, bringing most of the Warsaw Pact into NATO and encouraging the spread of market economies and democratic institutions throughout the former Communist world. It was a triumphal moment—the apogee of the American Era—but the celebratory fireworks blinded us to the trends and pitfalls that brought that era to an end.

THE PAST two decades have witnessed the emergence of new power centers in several key regions. The most obvious example is China, whose explosive economic growth is undoubtedly the most significant geopolitical development in decades. The United States has been the world’s largest economy since roughly 1900, but China is likely to overtake America in total economic output no later than 2025. Beijing’s military budget is rising by roughly 10 percent per year, and it is likely to convert even more of its wealth into military assets in the future. If China is like all previous great powers—including the United States—its definition of “vital” interests will grow as its power increases—and it will try to use its growing muscle to protect an expanding sphere of influence. Given its dependence on raw-material imports (especially energy) and export-led growth, prudent Chinese leaders will want to make sure that no one is in a position to deny them access to the resources and markets on which their future prosperity and political stability depend.

This situation will encourage Beijing to challenge the current U.S. role in Asia. Such ambitions should not be hard for Americans to understand, given that the United States has sought to exclude outside powers from its own neighborhood ever since the Monroe Doctrine. By a similar logic, China is bound to feel uneasy if Washington maintains a network of Asian alliances and a sizable military presence in East Asia and the Indian Ocean. Over time, Beijing will try to convince other Asian states to abandon ties with America, and Washington will almost certainly resist these efforts. An intense security competition will follow.

The security arrangements that defined the American Era are also being undermined by the rise of several key regional powers, most notably India, Turkey and Brazil. Each of these states has achieved impressive economic growth over the past decade, and each has become more willing to chart its own course independent of Washington’s wishes. None of them are on the verge of becoming true global powers—Brazil’s GDP is still less than one-sixth that of the United States, and India and Turkey’s economies are even smaller—but each has become increasingly influential within its own region. This gradual diffusion of power is also seen in the recent expansion of the G-8 into the so-called G-20, a tacit recognition that the global institutions created after World War II are increasingly obsolete and in need of reform.

Each of these new regional powers is a democracy, which means that its leaders pay close attention to public opinion. As a result, the United States can no longer rely on cozy relations with privileged elites or military juntas. When only 10–15 percent of Turkish citizens have a “favorable” view of America, it becomes easier to understand why Ankara refused to let Washington use its territory to attack Iraq in 2003 and why Turkey has curtailed its previously close ties with Israel despite repeated U.S. efforts to heal the rift. Anti-Americanism is less prevalent in Brazil and India, but their democratically elected leaders are hardly deferential to Washington either.

The rise of new powers is bringing the short-lived “unipolar moment” to an end, and the result will be either a bipolar Sino-American rivalry or a multipolar system containing several unequal great powers. The United States is likely to remain the strongest, but its overall lead has shrunk—and it is shrinking further still.

Of course, the twin debacles in Iraq and Afghanistan only served to accelerate the waning of American dominance and underscore the limits of U.S. power. The Iraq War alone will carry a price tag of more than $3 trillion once all the costs are counted, and the end result is likely to be an unstable quasi democracy that is openly hostile to Israel and at least partly aligned with Iran. Indeed, Tehran has been the main beneficiary of this ill-conceived adventure, which is surely not what the Bush administration had in mind when it dragged the country to war.

The long Afghan campaign is even more likely to end badly, even if U.S. leaders eventually try to spin it as some sort of victory. The Obama administration finally got Osama bin Laden, but the long and costly attempt to eliminate the Taliban and build a Western-style state in Afghanistan has failed. At this point, the only interesting question is whether the United States will get out quickly or get out slowly. In either scenario, Kabul’s fate will ultimately be determined by the Afghans once the United States and its dwindling set of allies leave. And if failure in Afghanistan weren’t enough, U.S. involvement in Central Asia has undermined relations with nuclear-armed Pakistan and reinforced virulent anti-Americanism in that troubled country. If victory is defined as achieving your main objectives and ending a war with your security and prosperity enhanced, then both of these conflicts must be counted as expensive defeats.

But the Iraq and Afghan wars were not simply costly self-inflicted wounds; they were also eloquent demonstrations of the limits of military power. There was never much doubt that the United States could topple relatively weak and/or unpopular governments—as it has in Panama, Afghanistan, Iraq and, most recently, Libya—but the wars in Iraq and Afghanistan showed that unmatched power-projection capabilities were of little use in constructing effective political orders once the offending leadership was removed. In places where local identities remain strong and foreign interference is not welcome for long, even a global superpower like the United States has trouble obtaining desirable political results.

Nowhere is this clearer than in the greater Middle East, which has been the main focus of U.S. strategy since the USSR broke apart. Not only did the Arab Spring catch Washington by surprise, but the U.S. response further revealed its diminished capacity to shape events in its favor. After briefly trying to shore up the Mubarak regime, the Obama administration realigned itself with the forces challenging the existing regional order. The president gave a typically eloquent speech endorsing change, but nobody in the region paid much attention. Indeed, with the partial exception of Libya, U.S. influence over the entire process has been modest at best. Obama was unable to stop Saudi Arabia from sending troops to Bahrain—where Riyadh helped to quell demands for reform—or to convince Syrian leader Bashar al-Assad to step down. U.S. leverage in the post-Mubarak political process in Egypt and the simmering conflict in Yemen is equally ephemeral.

One gets a vivid sense of America’s altered circumstances by comparing the U.S. response to the Arab Spring to its actions in the early years of the Cold War. In 1948, the Marshall Plan allocated roughly $13 billion in direct grants to restarting Europe’s economy, an amount equal to approximately 5 percent of total U.S. GDP. The equivalent amount today would be some $700 billion, and there is no way that Washington could devote even a tenth of that amount to helping Egypt, Tunisia, Libya or others. Nor does one need to go all the way back to 1948. The United States forgave $7 billion of Egypt’s foreign debt after the 1991 Gulf War; in 2011, all it could offer Cairo’s new government was $1 billion worth of loan guarantees (not actual loans) and $1 billion in debt forgiveness.

America’s declining influence is also revealed by its repeated failure to resolve the Israeli-Palestinian dispute. It has been nearly twenty years since the signing of the Oslo accords in September 1993, and the United States has had a monopoly on the “peace process” ever since that hopeful day. Yet its efforts have been a complete failure, proving beyond doubt that Washington is incapable of acting as an effective and evenhanded mediator. Obama’s call for “two states for two peoples” in his address to the Arab world in June 2009 produced a brief moment of renewed hope, but his steady retreat in the face of Israeli intransigence and domestic political pressure drove U.S. credibility to new lows.

Taken together, these events herald a sharp decline in America’s ability to shape the global order. And the recent series of economic setbacks will place even more significant limits on America’s ability to maintain an ambitious international role. The Bush administration inherited a rare budget surplus in 2001 but proceeded to cut federal taxes significantly and fight two costly wars. The predictable result was a soaring budget deficit and a rapid increase in federal debt, problems compounded by the financial crisis of 2007–09. The latter disaster required a massive federal bailout of the financial industry and a major stimulus package, leading to a short-term budget shortfall in 2009 of some $1.6 trillion (roughly 13 percent of GDP). The United States has been in the economic doldrums ever since, and there is scant hope of a rapid return to vigorous growth. These factors help explain Standard & Poor’s U.S. government credit-rating downgrade in August amid new fears of a “double-dip” recession.

Image: Pullquote: Instead of trying to be the “indispensable nation” nearly everywhere, the United States will need to figure out how to be the decisive power in the places that matter.Essay Types: Essay