IT SEEMED simple enough. The White House wants a surveillance drone to monitor an evolving showdown over human rights in Kyrgyzstan. A member of staff at the National Security Council calls the author, Rosa Brooks, at the Pentagon to tell her to send it on its way. Ms Brooks explains that this is not how the chain of command works in the military. Where would the drone come from? Which job would it no longer be doing? Who was going to pay for it? Whose airspace would it operate from? The incredulous response: “We’re talking about like, one drone. You’re telling me you can’t just call some colonel at CentCom and make this happen?”

The story illustrates two themes in an interesting and worrying book, “How Everything Became War and the Military Became Everything”. The first is the growing tendency of politicians and bureaucrats in Washington to turn to the armed forces when something, almost anything, needs doing. The second, despite or perhaps because of this, is the gulf in understanding that is making civil-military relations increasingly fraught. But Ms Brooks has a wider purpose, which is to examine what happens to institutions and legal processes when the distinctions between war and peace become blurred and the space between becomes the norm, as has happened in America in the decade and a half since the attacks of September 11th 2001.

Ms Brooks, a law professor at Georgetown University and a columnist for Foreign Policy, has direct experience of what she writes. Not only did she marry a lieutenant-colonel in the army’s special forces, but she went to work for the “vast, bureaucratic death-dealing enterprise”, otherwise known as the Pentagon, in 2009, serving for two years as an adviser to the formidable Michèle Flournoy (who would probably be defence secretary in a Clinton administration).

What she found there is that as the money available for conventional diplomacy and development aid precipitately declines, so the armed forces with their relatively inexhaustible resources are called upon to fill the gap. As one general puts it, the American military is becoming “a Super Walmart with everything under one roof”. Because its culture is proudly can-do, it gets on with the demands made on it without much complaint.

One consequence is that actual fighting has become something that only a small minority of soldiers do. Ms Brooks finds that through the recent, long wars most soldiers have spent their time supervising the building of wells, sewers and bridges, resolving community disputes, working with local police, writing press releases, analysing intelligence and so on. In many ways, Ms Brooks finds this admirable. The problem, she says, is that soldiers are not necessarily the best people to do this kind of work, lacking the inclination, the training or the experience to be much good at it.

The hope in the Pentagon nowadays is that it can return to its core purpose of deterring and preparing for proper, high-tech state-on-state wars. Counter-insurgency and nation-building have fallen out of fashion. Hillary Clinton has recently echoed Barack Obama in promising no “boots on the ground” in Iraq (despite the fact that there are about 5,000 pairs of them there and twice as many in Afghanistan). The reality is that you do not always get to choose the kind of wars you fight or how you fight them.

The muddying of the lines that normally exist between peace and war also has implications for what happens at home. Laws may be suspended or passed during a war that has a clear beginning and end without too much lasting damage. But when a state of semi-war becomes more or less permanent, the erosion of basic legal and democratic principles becomes a greater danger. The difficulty in closing down Guantánamo; the continuing arguments over where the line between vigorous interrogation and torture lies; the legal murkiness of using drones to carry out the targeted killing of America’s enemies are all reasons for concern.

Ms Brooks struggles to find solutions to these intractable problems. But she suggests that a more phlegmatic approach to the limited threat that terrorism really represents, along with an acceptance that eradicating it may not be possible, would allow people to think more clearly about how far they want to sacrifice civil liberties in responding to it.

She also calls for better understanding by politicians and national-security civilians of what the armed forces can and should be used for. Yet while she deplores the tendency to “dial 1-800-Military” whenever there is a problem, she sees no way out of the continuing expansion of the army’s role. If that is so, she argues, perhaps the best option is to start recruiting into the armed forces more of the kind of people who can respond effectively to a wide range of “complex and often inchoate threats” from refugee flows driven by climate change, ethnic conflicts, cyber-attacks or terrorists intent on developing biological weapons. In other words, military skills would be integrated with civilian skills “within a single large but agile organisation”. It is a nice idea. But one guaranteed to annoy almost everybody.