WHAT kind of armed forces does Britain need? In a dangerous and unpredictable world, how should the country spend its shrinking defence budget? Worryingly, it has put off answering these questions—and time for thinking is short. The next 18 months could determine whether the country remains a global military power or settles for inexorable military decline and growing irrelevance to its French and American allies.

In 2010 a new Conservative-led coalition government took an axe to defence, as it did to much other state spending. The Ministry of Defence’s budget was trimmed by 8%. On top of that, the department had to close a £45.6 billion ($76.2 billion) hole in the equipment budget, which had been mismanaged by the previous, Labour, government. Then the Treasury shifted the costs of running and upgrading Britain’s nuclear arsenal to the ministry. All told, the defence budget had to be cut by about a quarter—while Britain was still maintaining a large force in Afghanistan.

Along with this savage pruning came a hopeful vision of the armed forces. By 2020, it was hoped, Britain would have fewer infantry but a bigger, more potent reserve force. Though armoured vehicles and artillery would be cut, the country would have some fine equipment, including two new aircraft carriers and stealthy F-35 fighter jets to fly from them.

What the military establishment did not do—hardly surprisingly, given the urgent challenge of hacking back the defence budget—was to think seriously about the threats Britain was likely to face and what it could realistically accomplish. A national security strategy, published at the same time as the spending review, boasted that Britain’s strategic ambition was in no way diminished by the savaging of the defence budget. This seemed Panglossian at the time and has become more so as the Treasury continues to nibble at spending.

Strategy is not about having a perfect, comprehensive plan—an impossible goal. Rather, it involves working out the likelihood that the country will face various threats, and reshaping the military as far as limited resources allow so that it can adapt to deal with them.

Threats there are aplenty. Since the Arab spring, the arc of instability that is the Middle East and north Africa has worsened, menacing Europe. Meanwhile America is pivoting towards Asia. The Pentagon increasingly expects Europe—meaning mostly Britain and France—to look after security in its own neighbourhood.

Britain is little prepared for this. Like other Western countries, it continues to give too high a priority to fighting a war against a sophisticated adversary—something it is unlikely to have to do, Russia’s thuggish behaviour in the Ukraine notwithstanding. Britain gives too low a priority to the dangers posed by failing states and religious and ethnic struggles across Africa and the Middle East that are far more complex and wide-ranging than simply the export of terrorism.

Cuts to the armed forces have been strategically incoherent. David Cameron, the prime minister, promises to increase funding for military equipment by 1% a year in real terms after 2015. But the deep reductions to the Ministry of Defence’s budget, combined with the ever-rising cost of training and equipping a soldier, mean manpower is being slashed. The chief of the defence staff, General Sir Nick Houghton, has warned that Britain could end up with what Americans call a “hollow force”—an exquisitely equipped military that is short of trained men.

The pity of war

The political background is just as troubling. The British public admires its armed forces but seems increasingly reluctant to use them. Engagements in Iraq and Afghanistan have convinced people that interventions abroad are likely to turn into bloody, expensive failures. A vote in the House of Commons last August rejecting British participation in an American-led air strike on Syria reflected that mood. Political leaders have little appetite for trying to persuade the public that capable armed forces are essential to Britain’s future.

So there is an urgent need for a serious restatement of national strategy that could create a political consensus and inform Britain’s next strategic defence and security review (SDSR), due in 18 months. According to Paul Cornish, professor of strategic studies at Exeter University and an adviser to Sir Nick, this has yet to start. Nor is there much sign of direction from the top.

James Arbuthnot, the Tory chairman of the Commons defence committee, worries about government foot-dragging on the national security strategy. He says there is a “crisis of misunderstanding” about the value of the armed forces to the country. Mr Arbuthnot’s committee has urged the government to publish the new national security strategy well in advance of the SDSR. But Philip Hammond, the defence secretary, warns of the dangers of setting strategy without knowing how much money will be available to carry it through.

That points to another problem: political timing. The general election is scheduled for May 2015; the SDSR should be published five months later in October. Any work undertaken now will have to be finished off by a new government which might not feel bound by its predecessor’s decisions. Yet if the review does not start soon, it will be rushed and more likely to reach ill-considered conclusions.

The big problem, says Sir Hew Strachan, professor of the history of war at Oxford University, is that Westminster and Whitehall do not think strategically. Following the attack on the World Trade Centre in 2001, the concentration on terrorism as the principal existential threat facing the nation robbed British defence policy of coherence and credibility.

The solution should have been the national security council, established in 2010, which now has a secretariat of about 200 people sitting in the Cabinet Office. It is led by a national security adviser, Sir Kim Darroch, a foreign office mandarin. But critics say he and his team default to a civil service mentality that tends to be tactical rather than strategic.

Sir Hew argues the national security council has been a disappointment. In a recent book, “The Direction of War”, he argues that it fails to tackle crucial issues like the restructuring of the British army, and “prioritises the short-term and operational over the long-term and strategic.” Its secretariat lacks military expertise. Andrew Dorman, professor of international security at King’s College London, thinks the national security adviser should be a big-hitting political figure with cabinet rank rather than a civil servant, even though departmental ministers might not like it.

For now the process seems rudderless. When Mr Cameron was asked a few weeks ago who would be in charge of the strategy review, the man known as the “essay-crisis prime minister” for his tendency to take decisions at the last minute said that he would lead it. But he has shown no inclination to start the process.

With its geography, history and open economy, Britain knows that its prosperity and security depend on the rules-based international order and being willing to uphold it when it is threatened. The 2015 SDSR is an opportunity to bring together the elements required for a modern national strategy to do this. As things stand, it seems likely to be squandered.