Today, it is difficult even to imagine the magnitude of the British Empire. At its height, it covered about a quarter of the earth's land surface and included a quarter of its population. London's network of colonies, territories, bases, and ports spanned the globe. The empire was protected by the Royal Navy, the greatest seafaring force in history, and linked by 170,000 nautical miles of ocean cables and 662,000 miles of aerial and buried cables. British ships had facilitated the development of the first global communications network, via the telegraph. Railways and canals (the Suez Canal most importantly) deepened the connectivity of the system. Through all of this, the British Empire created the first truly global market. Americans often talk about the appeal of their culture and ideas, but "soft power" really began with Britain. The historian Claudio Vliz points out that in the seventeenth century, the two imperial powers of the day, Britain and Spain, both tried to export their ideas and practices to their western colonies. Spain wanted the Counter-Reformation to take hold in the New World; Britain wanted religious pluralism and capitalism to flourish. As it turned out, British ideas proved more universal. In fact, Britain has arguably been the most successful exporter of its culture in human history. Before the American dream, there was an "English way of life" -- one that was watched, admired, and copied throughout the world. And also thanks to the British Empire, English spread as a global language, spoken from the Caribbean to Cape Town to Calcutta. Not all of this was recognized in June 1897, but much of it was. The British were hardly alone in making comparisons between their empire and Rome. Paris' Le Figaro declared that Rome itself had been "equaled, if not surpassed, by the Power which in Canada, Australia, India, in the China Seas, in Egypt, Central and Southern Africa, in the Atlantic and in the Mediterranean rules the peoples and governs their interests." The Kreuz-Zeitung in Berlin described the empire as "practically unassailable." Across the Atlantic, The New York Times gushed, "We are a part, and a great part, of the Greater Britain which seems so plainly destined to dominate this planet." Britain's exalted position, however, was more fragile than it appeared. Just two years after the Diamond Jubilee, Britain entered the Boer War, a conflict that, for many scholars, marks the moment when British power began to decline. London was sure that it would win the fight with little trouble. After all, the British army had just won a similar battle against the dervishes in Sudan, despite being outnumbered by more than two to one. In the Battle of Omdurman, it inflicted 48,000 dervish casualties in just five hours while losing only 48 soldiers of its own. Many in Britain imagined an even easier victory against the Boers. After all, as one member of Parliament put it, it was "the British Empire against 30,000 farmers." The war was ostensibly fought for a virtuous reason: to defend the rights of the English-speaking people of the Boer republics, who were treated as second-class citizens by the ruling Boers. But it did not escape the attention of London that after the discovery of gold in the region in 1886, these republics had been producing a quarter of the world's gold supply. In any event, the Boers launched a preemptive strike, and war began in 1899. Things went badly for Britain from the beginning. It had more men and better weapons and was fielding its best generals (including Lord Kitchener, the hero of Omdurman). But the Boers were passionate in defending themselves, knew the land, and adopted successful guerrilla tactics that relied on stealth and speed. The British army's enormous military superiority meant little on the ground, and its commanders resorted to brutal tactics -- burning down villages, herding civilians into concentration camps (the world's first), sending in more and more troops. Eventually, Britain had 450,000 troops fighting a militia of 45,000. The Boers could not hold back the British army forever, and in 1902 they surrendered. But in a larger sense, Britain lost the war. It had suffered 45,000 casualties, spent half a billion pounds, stretched its army to the breaking point, and discovered enormous incompetence and corruption in its war effort. Its brutal wartime tactics, moreover, gave it a black eye in the view of the rest of the world. At home, all of this created, or exposed, deep divisions over Britain's global role. Abroad, every other great power -- France, Germany, the United States -- opposed London's actions. "They were friendless," the historian Lawrence James has written of the British in 1902. Fast-forward to today. Another superpower, militarily unbeatable, wins an easy victory in Afghanistan and then takes on what it is sure will be another simple battle, this one against Saddam Hussein's isolated regime in Iraq. The result: a quick initial military victory followed by a long, arduous struggle, filled with political and military blunders and met with intense international opposition. The analogy is obvious; the United States is Britain, the Iraq war is the Boer War -- and, by extension, the United States' future looks bleak. And indeed, regardless of the outcome in Iraq, the costs have been massive. The United States has been overextended and distracted, its army stressed, its image sullied. Rogue states such as Iran and Venezuela and great powers such as China and Russia are taking advantage of Washington's inattention and bad fortunes. The familiar theme of imperial decline is playing itself out one more time. History is happening again. The Long Goodbye But whatever the apparent similarities, the circumstances are not really the same. Britain was a strange superpower. Historians have written hundreds of books explaining how London could have adopted certain foreign policies to change its fortunes. If only it had avoided the Boer War, say some. If only it had stayed out of Africa, say others. The historian Niall Ferguson provocatively suggests that had Britain stayed out of World War I (and there might not have been a world war without British participation), it might have managed to preserve its great-power position. There is some truth to this line of reasoning (World War I did bankrupt Britain), but to put things properly in historical context, it is worth looking at this history from another angle. Britain's immense empire was the product of unique circumstances. The wonder is not that it declined but that its dominance lasted as long as it did. Understanding how Britain played its hand -- one that got weaker over time -- can help illuminate the United States' path forward. Britain has been a rich country for centuries (and was a great power for most of that time), but it was an economic superpower for little more than a generation. Observers often make the mistake of dating its apogee by great imperial events such as the Diamond Jubilee. In fact, by 1897, Britain's best years were already behind it. Its true apogee was a generation earlier, from 1845 to 1870. At the time, it was producing more than 30 percent of global GDP. Its energy consumption was five times that of the United States and 155 times that of Russia. It accounted for one-fifth of the world's trade and two-fifths of its manufacturing trade. And all this was accomplished with just two percent of the world's population. By the late 1870s, the United States had equaled Britain on most industrial measures, and by the early 1880s it had actually surpassed it, as Germany would about 15 years later. By World War I, the United States' economy was twice the size of Britain's, and together France's and Russia's were larger as well. In 1860, Britain had produced 53 percent of the world's iron (then a sign of supreme industrial strength); by 1914, it was making less than 10 percent. Of course, politically, London was still the capital of the world at the time of World War I, and its writ was unequaled and largely unchallenged across much of the globe. Britain had acquired an empire in a period before the onset of nationalism, and so there were few obstacles to creating and maintaining control in far-flung places. Its sea power was unrivaled, and it remained dominant in banking, shipping, insurance, and investment. London was still the center of global finance, and the pound still the reserve currency of the world. Even in 1914, Britain invested twice as much capital abroad as its closest competitor, France, and five times as much as the United States. The economic returns of these investments and other "invisible trades" in some ways masked Britain's decline. In fact, the British economy was sliding. British growth rates had dropped below two percent in the decades leading up to World War I. The United States and Germany, meanwhile, were growing at around five percent. Having spearheaded the first Industrial Revolution, Britain was less adept at moving into the second. The goods it was producing represented the past rather than the future. In 1907, for example, it manufactured four times as many bicycles as the United States did, but the United States manufactured 12 times as many cars. Scholars have debated the causes of Britain's decline since shortly after that decline began. Some have focused on geopolitics; others, on economic factors, such as low investment in new plants and equipment and bad labor relations. British capitalism had remained old-fashioned and rigid, its industries set up as small cottage-scale enterprises with skilled craftsmen rather than the mass factories that sprang up in Germany and the United States. There were signs of broader cultural problems as well. A wealthier Britain was losing its focus on practical education, and British society retained a feudal cast, given to it by its landowning aristocracy. But it may be that none of these failings was actually crucial. The historian Paul Kennedy has explained the highly unusual circumstances that produced Britain's dominance in the nineteenth century. Given its portfolio of power -- geography, population, resources -- Britain could reasonably have expected to account for three to four percent of global GDP, but its share rose to around ten times that figure. As those unusual circumstances abated -- as other Western countries caught up with industrialization, as Germany united, as the United States resolved its North-South divide -- Britain was bound to decline. The British statesman Leo Amery saw this clearly in 1905. "How can these little islands hold their own in the long run against such great and rich empires as the United States and Germany are rapidly becoming?" he asked. "How can we with forty millions of people compete with states nearly double our size?" It is a question that many Americans are now asking in the face of China's rise. Britain managed to maintain its position as the leading world power for decades after it lost its economic dominance thanks to a combination of shrewd strategy and good diplomacy. Early on, as it saw the balance of power shifting, London made one critical decision that extended its influence by decades: it chose to accommodate itself to the rise of the United States rather than to contest it. In the decades after 1880, on issue after issue London gave in to a growing and assertive Washington. It was not easy for Britain to cede control to its former colony, a country with which it had fought two wars and in whose recent civil war it had sympathized with the secessionists. But it was a strategic masterstroke. Had Britain tried to resist the rise of the United States, on top of all its other commitments, it would have been bled dry. For all of London's mistakes over the next half century, its strategy toward Washington -- one followed by every British government since the 1890s -- meant that Britain could focus its attention on other critical fronts. It remained, for example, the master of the seas, controlling its lanes and pathways with "five keys" that were said to lock up the world -- Singapore, the Cape of Good Hope, Alexandria, Gibraltar, and Dover. Britain maintained control of its empire and retained worldwide influence with relatively little opposition for many decades. (In the settlement after World War I, it took over 1.8 million square miles of territory and 13 million new subjects, mostly in the Middle East.) Still, the gap between its political role and its economic capacity was growing. By the twentieth century, the empire was an enormous drain on the British treasury. And this was no time for expensive habits. The British economy was reeling. World War I cost over $40 billion, and Britain, once the world's leading creditor, had debts amounting to 136 percent of domestic output afterward. By the mid-1920s, interest payments alone sucked up half the government's budget. Meanwhile, by 1936, Germany's defense spending was three times as high as Britain's. The same year that Italy invaded Ethiopia, Mussolini also placed 50,000 troops in Libya -- ten times the number of British troops guarding the Suez Canal. It was these circumstances -- coupled with the memory of a recent world war that had killed more than 700,000 young Britons -- that led the British governments of the 1930s, facing the forces of fascism, to prefer wishful thinking and appeasement to confrontation. World War II was the final nail in the coffin of British economic power: in 1945, the United States' GDP was ten times that of Britain. Even then, Britain remained remarkably influential, at least partly because of the almost superhuman energy and ambition of Winston Churchill. Given that the United States was paying most of the Allies' economic costs, and Russia was bearing most of the casualties, it took extraordinary will for Britain to remain one of the three major powers deciding the fate of the postwar world. (The photographs of Franklin Roosevelt, Joseph Stalin, and Churchill at the Yalta Conference in February 1945 are somewhat misleading: there was no "big three" at Yalta; there was a "big two" plus one brilliant political entrepreneur who was able to keep himself and his country in the game.) But even this came at a cost. In return for its loans to London, the United States took over dozens of British bases in Canada, the Caribbean, the Indian Ocean, and the Pacific. "The British Empire is handed over to the American pawnbroker -- our only hope," said one member of Parliament. The economist John Maynard Keynes described the Lend-Lease Act as an attempt to "pick out the eyes of the British Empire." Less emotional observers saw that the transition was inevitable. Toynbee, by then a distinguished historian, consoled Britons by noting that the United States' "hand will be a great deal lighter than Russia's, Germany's, or Japan's, and I suppose these are the alternatives." The Entrepreneurial EmpireBritain was undone as a global power not because of bad politics but because of bad economics. Indeed, the impressive skill with which London played its weakening hand despite a 70-year economic decline offers important lessons for the United States. First, however, it is essential to note that the central feature of Britain's decline -- irreversible economic deterioration -- does not really apply to the United States today. Britain's unrivaled economic status lasted for a few decades; the United States' has lasted more than 120 years. The U.S. economy has been the world's largest since the middle of the 1880s, and it remains so today. In fact, the United States has held a surprisingly constant share of global GDP ever since. With the brief exception of the late 1940s and 1950s, when the rest of the industrialized world had been destroyed and its share rose to 50 percent, the United States has accounted for roughly a quarter of world output for over a century (32 percent in 1913, 26 percent in 1960, 22 percent in 1980, 27 percent in 2000, and 26 percent in 2007). It is likely to slip, but not significantly, in the next two decades. Most estimates suggest that in 2025 the United States' economy will still be twice the size of China's in terms of nominal GDP. This difference between the United States and Britain is reflected in the burden of their military budgets. Britannia ruled the seas but never the land. The British army was sufficiently small that Otto von Bismarck once quipped that were the British ever to invade Germany, he would simply have the local police force arrest them. Meanwhile, London's advantage over the seas -- it had more tonnage than the next two navies put together -- came at ruinous cost. The U.S. military, in contrast, dominates at every level -- land, sea, air, space -- and spends more than the next 14 countries combined, accounting for almost 50 percent of global defense spending. The United States also spends more on defense research and development than the rest of the world put together. And crucially, it does all this without breaking the bank. U.S. defense expenditure as a percent of GDP is now 4.1 percent, lower than it was for most of the Cold War (under Dwight Eisenhower, it rose to ten percent). As U.S. GDP has grown larger and larger, expenditures that would have been backbreaking have become affordable. The Iraq war may be a tragedy or a noble endeavor, but either way, it will not bankrupt the United States. The price tag for Iraq and Afghanistan together -- $125 billion a year -- represents less than one percent of GDP. The war in Vietnam, by comparison, cost the equivalent of 1.6 percent of U.S. GDP in 1970, a large difference. (Neither of these percentages includes second- or third-order costs of war, which allows for a fair comparison even if one disputes the exact figures.) U.S. military power is not the cause of its strength but the consequence. The fuel is the United States' economic and technological base, which remains extremely strong. The United States does face larger, deeper, and broader challenges than it has ever faced in its history, and it will undoubtedly lose some share of global GDP. But the process will look nothing like Britain's slide in the twentieth century, when the country lost the lead in innovation, energy, and entrepreneurship. The United States will remain a vital, vibrant economy, at the forefront of the next revolutions in science, technology, and industry. In trying to understand how the United States will fare in the new world, the first thing to do is simply look around: the future is already here. Over the last 20 years, globalization has been gaining breadth and depth. More countries are making goods, communications technology has been leveling the playing field, capital has been free to move across the world -- and the United States has benefited massively from these trends. Its economy has received hundreds of billions of dollars in investment, and its companies have entered new countries and industries with great success. Despite two decades of a very expensive dollar, U.S. exports have held ground, and the World Economic Forum currently ranks the United States as the world's most competitive economy. GDP growth, the bottom line, has averaged just over three percent in the United States for 25 years, significantly higher than in Europe or Japan. Productivity growth, the elixir of modern economics, has been over 2.5 percent for a decade now, a full percentage point higher than the European average. This superior growth trajectory might be petering out, and perhaps U.S. growth will be more typical for an advanced industrialized country for the next few years. But the general point -- that the United States is a highly dynamic economy at the cutting edge, despite its enormous size -- holds. Consider the industries of the future. Nanotechnology (applied science dealing with the control of matter at the atomic or molecular scale) is likely to lead to fundamental breakthroughs over the next 50 years, and the United States dominates the field. It has more dedicated "nanocenters" than the next three nations (Germany, Britain, and China) combined and has issued more patents for nanotechnology than the rest of the world combined, highlighting its unusual strength in turning abstract theory into practical products. Biotechnology (a broad category that describes the use of biological systems to create medical, agricultural, and industrial products) is also dominated by the United States. Biotech revenues in the United States approached $50 billion in 2005, five times as large as the amount in Europe and representing 76 percent of global biotech revenues. Manufacturing has, of course, been leaving the country, shifting to the developing world and turning the United States into a service economy. This scares many Americans, who wonder what their country will make if everything is "made in China." But Asian manufacturing must be viewed in the context of a global economy. The Atlantic Monthly's James Fallows spent a year in China watching its manufacturing juggernaut up close, and he provides a persuasive explanation of how outsourcing has strengthened U.S. competitiveness. What it comes down to is that the real money is in designing and distributing products -- which the United States dominates -- rather than manufacturing them. A vivid example of this is the iPod: it is manufactured mostly outside the United States, but most of the added value is captured by Apple, in California. Many experts and scholars, and even a few politicians, worry about certain statistics that bode ill for the United States. The U.S. savings rate is zero; the current account deficit, the trade deficit, and the budget deficit are high; the median income is flat; and commitments for entitlements are unsustainable. These are all valid concerns that will have to be addressed. But it is important to keep in mind that many frequently cited statistics offer only an approximate or an antiquated measure of an economy. Many of them were developed in the late nineteenth century to describe industrial economies with limited cross-border activity, not modern economies in today's interconnected global market. For the last two decades, for example, the United States has had unemployment rates well below levels economists thought possible without driving up inflation. Or consider that the United States' current account deficit -- which in 2007 reached $800 billion, or seven percent of GDP -- was supposed to be unsustainable at four percent of GDP. The current account deficit is at a dangerous level, but its magnitude can be explained in part by the fact that there is a worldwide surplus of savings and that the United States remains an unusually stable and attractive place to invest. The decrease in personal savings, as the Harvard economist Richard Cooper has noted, has been largely offset by an increase in corporate savings. The U.S. investment picture also looks much rosier if education and research-and-development spending are considered along with spending on physical capital and housing. The United States has serious problems. By all calculations, Medicare threatens to blow up the federal budget. The swing from surpluses to deficits between 2000 and 2008 has serious implications. Growing inequality (the result of the knowledge economy, technology, and globalization) has become a signature feature of the new era. Perhaps most worrying, Americans are borrowing 80 percent of the world's surplus savings and using it for consumption: they are selling off their assets to foreigners to buy a couple more lattes a day. But such problems must be considered in the context of an overall economy that remains powerful and dynamic. Education Nation"Ah, yes," say those who are more worried, "but you are looking at a snapshot of today. The United States' advantages are rapidly eroding as the country loses its scientific and technological base and suffers from inexorable cultural decay." A country that once adhered to a Puritan ethic of delayed gratification, the argument goes, has become one that revels in instant pleasures; Americans are losing interest in the basics -- math, manufacturing, hard work, savings -- and becoming a society that specializes in consumption and leisure. No statistic seems to capture this anxiety better than those showing the decline of engineering in the United States. In 2005, the National Academy of Sciences released a report warning that the United States could soon lose its privileged position as the world's science leader. The report said that in 2004 China graduated 600,000 engineers, India 350,000, and the United States 70,000 -- numbers that were repeated in countless articles, books, and speeches. And indeed, these figures do seem to be cause for despair. What hope does the United States have if for every one qualified American engineer there are more than a dozen Chinese and Indian ones? For the cost of one chemist or engineer in the United States, the report pointed out, a company could hire five Chinese chemists or 11 Indian engineers. The numbers, however, are wrong. Several academics and journalists investigated the matter and quickly realized that the Asian totals included graduates of two- or three-year programs training students in simple technical tasks. The National Science Foundation, which tracks these statistics in the United States and other nations, puts the Chinese number at about 200,000 engineering degrees per year, and the Rochester Institute of Technology's Ron Hira puts the number of Indian engineering graduates at about 125,000 a year. This means that the United States actually trains more engineers per capita than either China or India does. And the numbers do not address the issue of quality. The best and brightest in China and India -- those who, for example, excel at India's famous engineering academies, the Indian Institutes of Technology (5,000 out of 300,000 applicants make it past the entrance exams) -- would do well in any educational system. But once you get beyond such elite institutions -- which graduate under 10,000 students a year -- the quality of higher education in China and India remains extremely poor, which is why so many students leave those countries to get trained abroad. In 2005, the McKinsey Global Institute did a study of "the emerging global labor market" and found that 28 low-wage countries had approximately 33 million young professionals at their disposal. But, the study noted, "only a fraction of potential job candidates could successfully work at a foreign company," largely because of inadequate education. Indeed, higher education is the United States' best industry. In no other field is the United States' advantage so overwhelming. A 2006 report from the London-based Center for European Reform points out that the United States invests 2.6 percent of its GDP in higher education, compared with 1.2 percent in Europe and 1.1 percent in Japan. Depending on which study you look at, the United States, with five percent of the world's population, has either seven or eight of the world's top ten universities and either 48 percent or 68 percent of the top 50. The situation in the sciences is particularly striking. In India, universities graduate between 35 and 50 Ph.D.'s in computer science each year; in the United States, the figure is 1,000. A list of where the world's 1,000 best computer scientists were educated shows that the top ten schools are all American. The United States also remains by far the most attractive destination for students, taking in 30 percent of the total number of foreign students globally, and its collaborations between business and educational institutions are unmatched anywhere in the world. All these advantages will not be erased easily, because the structure of European and Japanese universities -- mostly state-run bureaucracies -- is unlikely to change. And although China and India are opening new institutions, it is not that easy to create a world-class university out of whole cloth in a few decades. Few people believe that U.S. primary and secondary schools deserve similar praise. The school system, the line goes, is in crisis, with its students performing particularly badly in science and math, year after year, in international rankings. But the statistics here, although not wrong, reveal something slightly different. The real problem is one not of excellence but of access. The Trends in International Mathematics and Science Study (TIMSS), the standard for comparing educational programs across nations, puts the United States squarely in the middle of the pack. The media reported the news with a predictable penchant for direness: "Economic Time Bomb: U.S. Teens Are Among Worst at Math," declared The Wall Street Journal. But the aggregate scores hide deep regional, racial, and socioeconomic variation. Poor and minority students score well below the U.S. average, while, as one study noted, "students in affluent suburban U.S. school districts score nearly as well as students in Singapore, the runaway leader on TIMSS math scores." The difference between the average science scores in poor and wealthy school districts within the United States, for instance, is four to five times as high as the difference between the U.S. and the Singaporean national average. In other words, the problem with U.S. education is a problem of inequality. This will, over time, translate into a competitiveness problem, because if the United States cannot educate and train a third of the working population to compete in a knowledge economy, this will drag down the country. But it does know what works. The U.S. system may be too lax when it comes to rigor and memorization, but it is very good at developing the critical faculties of the mind. It is surely this quality that goes some way in explaining why t