“AMATEURS TALK STRATEGY, professionals talk capacity.” Jeremy Shapiro, who recently left the State Department to join the Brookings Institution in Washington, has put his finger on a central question for foreign policy. For the liberal, open-market system to endure is in America’s interest—and in the general interest, too. America does not yet face a direct challenge from China and Russia. But as the dominant power it must be able and willing to maintain the system, or norms will fray and tensions grow. Does it have the capacity?

The question forces itself on policymakers just now because the demands placed on American primacy have changed. In the cold war, explains John Ikenberry, an academic, America provided security and other services to many countries. But the threat is no longer so great and security is therefore no longer so valuable. For many countries in large parts of the world, the past decade has been not about war and financial crisis but about peace and prosperity. Those countries want more of a say.

At the same time, according to Moisés Naím of the Carnegie Endowment for International Peace, the old centres of power, including governments, have less room for manoeuvre. Their authority to dictate values and behaviour has been undermined by a profusion of new political actors and interest groups who are mobile and connected.

Some conclude that in such a world dominance is impossible: there are too many actors with the power to block anything they dislike. The rest of this special report will examine how far that is true by looking at the components of American primacy—sharp military power, sticky economic power and the sweet power of American values—before drawing some conclusions about how America should act. In each case, as Mr Shapiro has observed, the starting point is capacity.

Seen from Washington, the main threat to America’s armed forces is to be found not in Helmand or Hainan but in the automatic budget cuts of the sequester. This roughly doubles the savings that will have to come from the Pentagon’s budget in the next nine years, to about $1 trillion.

During the summer Chuck Hagel, the defence secretary, mapped out a possible first round of cuts: shrinking the army by up to 110,000 troops from its current target of 490,000; and losing possibly two of ten aircraft-carriers, as well as bombers and transport aircraft. The alternative, Mr Hagel said, was to cut spending on modernisation.

Cut, but not to the quick

Inevitably, the proposed cuts have stirred up a hornets’ nest. But just how bad are they? In the ten years to 2011, when America was at war, pay and benefits for the army increased by 57% in real terms. The number of support staff, too, grew rapidly. Because Congress will not touch this large and politically sensitive part of the budget, the cuts must be borne elsewhere.

That is a foolish way to run an army. However, even without the sequester, much of the enormous build-up in spending after the attacks of September 11th 2001 should be going into reverse. Moreover, America’s military might will remain unchallenged, even after the cuts. Just after Mr Hagel set out his ideas, the vice-chairman of the Joint Chiefs of Staff told Congress about the Pentagon’s revised plans for potential wars around the world. Large invasions may be out, but it can draw on quick-reaction forces and stealth air power and ships. And not only does it outspend most of the rest of the world combined on conventional defence (see chart 3), it also has a formidable nuclear arsenal and the wherewithal for cyber-warfare. The real question is not whether the country can go to war if it has to, but whether it fights the right sort of war when it chooses to. Modern America has shown an unrivalled appetite for battle. During more than half the years since the end of the cold war it has been in combat. That is not just because of the war in Iraq, which lasted from 2003 to 2011, and that in Afghanistan, which began two years earlier and is still unfinished. Even before that, between 1989 and 2001 the United States intervened abroad on average once every 16 months—more frequently than in any period in its history. Few are happy about this, especially America’s senior officers. “It’s too easy to use force,” says Admiral Mike Mullen, a former chairman of the Joint Chiefs of Staff. “It’s almost the first choice.” General Brent Scowcroft, national-security adviser to Gerald Ford and the elder George Bush, agrees. One reason why politicians have turned to the armed forces, he argues, is that war looks like a shortcut to success. Trying to change people’s minds and influence them in other ways is long and slow. “The fallacy is that often the use of force changes the circumstances of the question. By the time you have finished, the question is different and we frequently find ourselves in an unanticipated situation.” That was particularly true of Afghanistan and Iraq. The consensus now is that the first war has been unhappy and the second was a mistake. The Iraqi campaign (which The Economist also supported, to the irritation of many of its readers) especially provokes the experts. A “fiasco” and a “catastrophe”, they say; “a 15-year detour” that “sullied America’s moral leadership”. America needs to look squarely at why it found these two wars so hard to help it decide which wars to take on in future.

The end of the beginning in Iraq The basic armoured set-piece on a defined battlefield in which one side wins and the other loses now rarely happens in real life. The past few decades have seen no absolute defeat in the style of Berlin in 1945. Even the most successful recent campaign, the first Gulf war of 1990, left Saddam Hussein in power and at liberty to go on murdering his own people. America went to war for a second time in Iraq in 2003 thinking that the fight was a big armoured assault, only to discover that it had stumbled into a seemingly endless insurgency like the one already under way in Afghanistan. Both were a bit like the Vietnam war, but the army had been so keen to forget Indochina that it had to learn the art of counter-insurgency all over again. What did it discover? First, that war is even more political than it used to be. Emile Simpson, who was an infantry officer in the Royal Gurkha Rifles and served three tours in Afghanistan, argues that modern war is not defined against the enemy alone. Far beyond the battlefields of Uruzgan province in southern Afghanistan are other audiences, including the Afghan people, the Muslim world, NATO, China and voters back home. The idea of defeating the Taliban in Afghanistan has become ever less relevant. To the politicians in charge and to the overall national interest, the other audiences have counted just as much, if not more. When groups far from the fighting matter, the foundations of warfare shift all the time. Military strategy needs to evolve to take account of all those other audiences. A drone strike like the recent one that killed the leader of the Pakistani Taliban might help defeat the insurgents but undermine the coalition among other groups. Just as you do not win an election by destroying the other party, so you do not win such a war by destroying the enemy. You have to destroy the enemy’s legitimacy. When the battlefield is diffuse, you get cross-cutting franchises rather than two opposing sides. In Afghanistan the foreign forces were co-opted into tribal and ethnic conflicts that had existed long before they arrived. The allocation of resources was designed to keep the base of supporters as well as win over new ones. It was not about conquering territory and moving forward. America and its allies were dragged into battles that had no clean military solution. Winning the trial of strength could not win over the people: the idea was not destruction but persuasion. If they had sought to destroy the insurgents with raw power, audiences away from the battle would have objected.

The second lesson America’s armed forces learned is that counter-insurgency, or COIN, is drawn out and hard to pull off. One study looking at the past few decades found that only a quarter of COIN campaigns have succeeded—though this may be partly because fights against insurgencies often start as if they were traditional wars. The campaigns tend to last at least 14 years, which means they have to be sustained during at least four American presidential terms.

Richard Betts, of New York’s Columbia University, notes that this is all the more demanding because COIN requires a lot of manpower. Insurgents are prepared to bear heavy casualties. Ho Chi Minh told the French in 1946 that “you will kill ten of our men and we will kill one of yours, and in the end it will be you who tire of it.” That was more or less what happened.

The force ratio that is often suggested is 20 soldiers for every 1,000 citizens, which works out at about 650,000 troops for Iraq and 600,000 for Afghanistan. The implication is that an insurgency has to be either in a small country or be restricted to a region in a large one. The danger, says Mr Betts, is that the force you send in is too weak to pacify the territory or too big and clumsy to win over the local population.

Humanitarian operations pose an extra problem. Military interventions in small countries, as in Sierra Leone in 2000, have often been successful; in larger ones, such as Sudan, less so. Humanitarian forces seek to be impartial and tend to be small, because the war is voluntary and domestic political support may not last. Mr Betts points out that this combination often only prolongs the fighting. When you are imposing peace, you need either to take sides and send in a small force that can tip the balance and bring the fighting to an end; or remain neutral and send in a large force which can keep the warring sides apart but will probably be stuck in the country for years.

The view from the ground

Many think that in future America can simply avoid such entanglements. Instead, they say, it can restrict itself to big state-on-state “wars of necessity”. American forces are world leaders in this kind of fighting. Any other business can be mopped up by the redoubtable special-operations forces, such as the Navy SEALs who killed Osama bin Laden.

But this is an oversimplification. At the margin, “of necessity” tends to mean nothing more than “justifiable”. Whether the country needs to go to war is always unclear before the fighting starts. Many Americans thought that even Hitler’s Germany should not be attacked—until Japan bombed the American fleet in Hawaii.

Besides, wars of choice might sometimes be worth fighting. Imagine, for instance, engaging a band of jihadists who were repeatedly attacking American interests in a lawless land; or perhaps dealing with a country bent on nuclear proliferation. And what should America do about a nation devastated by genocide, as the Armenians were a century ago?

Even in a war of necessity America often cannot force an enemy to fight on its terms. Conrad Crane, a military historian and author of the COIN manual for Iraq, has observed that “there are two types of warfare, asymmetric and stupid.” The enemy might refuse to fight a stupid war.

Michèle Flournoy, a former Pentagon official, thinks that the army should therefore continue to train its soldiers for COIN among other missions even though, after more than a decade spent fighting insurgents, it has had enough. As today’s troops retire, she says, COIN techniques risk being forgotten. Her fear is well-founded. The Pentagon is preoccupied not by doctrine or the enemy abroad but by budgets and the enemy in Washington.

Limited wars tend to be long and hard, so America needs a clear sense of what it is trying to achieve before the first shot is fired. As Admiral Mullen puts it, “I am tired of interventionists picking up a stick without a strategy, without knowing the political and diplomatic outcome.” Although such wars cannot be avoided altogether, in future America should aim to fight them less often and more wisely.