Soon, openly gay servicemen and women will be able to serve without reprisal. Harvard has re-instated its Reserve Officers Training Corps. This seems to many like progress. But who would recommend in these days of the all-volunteer force that anyone, straight or gay, Ivy or enlisted, go into the military at all?

The class of 2011 at the US Naval Academy, where I have served 24 years as a professor, has just graduated and its members have become officers. As have the classes of the other service academies. They should know what they are about to embark upon: A futile effort? A noble endeavor? A job with guaranteed benefits that may have them coming back in a box or spending years in rehab?

We got Osama bin Laden, but the euphoria will fade and the fight against terrorism will go on. Indeed, after a decade of US military intervention in the greater Middle East, the benefits – even the point – of shedding our blood and treasure seem elusive at best. We should tell our young soldiers what, exactly, they are defending.

How should the military see itself in this age where victory is unclear and the value of violent intervention so nebulous? Why should anyone join the military, either as an officer or as an enlisted person? Is it all about paying for college, having a steady income, or escaping a stifling small town or inner city? US military leaders give no clear answers. Yet these are the questions we must ask.

What's the point?

Volunteering to fight is never easy, but the sacrifice is more tolerable when the military's purpose is clear – something it hasn't been for years.

My students are graduating at the end of a decade of US military interventions gone awry. Outgoing Secretary of Defense Robert Gates says that any future secretary who advises a president to send a big land army into Asia, the Middle East, or Africa "ought to have his head examined." Gen. David Petraeus emphasizes the gains in an increasingly less-violent Afghanistan, but others warn that the gains may evaporate at our departure. And now the United States has become involved in bombing Libya, ostensibly to protect civilians but also apparently to aid rebels who seem incapable of ousting Muammar Qaddafi on their own.

Certainly the military's purpose is nowhere near so clear as when we could explain it in terms of national defense. After the Japanese attacked Pearl Harbor, declaring war was a no-brainer. What are we defending ourselves against in Libya? The George W. Bush administration tried to define a tactic as the enemy in its phrase Global War on Terror. GWOT casualties are listed on the stadium where our graduation takes place next to those of other conflicts like Vietnam and Korea. Yet now the phrase GWOT has been retired. So who or what is the enemy?

Increasingly, polls show, Americans feel that there is no point to the war in Afghanistan. Al Qaeda simply goes across the border to Pakistan. Theorists and pundits spar over whether "nation building" is a legitimate enterprise for the US military. The counterinsurgency movement, COIN, that has apparently stabilized the situation in Iraq and Afghanistan, seems increasingly to be about locals lining up to accept our payoffs – and offering no loyalty past the day the payoffs stop. War is just bribery by other means, as the celebrated Prussian theorist Carl von Clausewitz might have said.

A discouraging time

What a discouraging time to be going into the military. Yet only die-hard pacifists want to abolish the military in a world full of malefactors. How can we encourage our young people to go into it nowadays if we don't have any idea what it is or what it does?

The US military today is neither of the two militaries that, in historical terms, have had a coherent metaphysical base. For the ancient Greeks, war was virtually an annual event: All male citizens got involved for a short time. For the ancient Hindus of the Sanskrit epics, war was something you were, the calling of caste.

What is the military for Americans today? Neither of these. Nor is it the if-you-survive-you-come-back-rich scheme of the early Modern Era, as late as Napoleon.

What clearly is a nonstarter is the justification for serving that the military, against all logic, actually proposes to its people nowadays: that those in the military are morally better ("held to a higher standard") than the civilians they defend. You're better people, the military tells those who join it: more loyal, more self-sacrificing, and tougher. But if this is true, why put your life on the line to defend these lamentable civilians?

We need a new military metaphysics, a coherent view of the role of an all-volunteer force in a complex, multipolar world. This view has to acknowledge that national defense is not always the main reason for using the military. It has to acknowledge that the military can be misused by civilian politicians out to seem tough, or working on their "legacy." It has to know that history may judge harshly the "worthy" and "noble" campaigns that cost too many soldiers their lives and limbs.

Always ready

It needs to offer a pride that's not bought at the cost of denigrating the civilians the military exists to protect. This needs to be a pride in doing a sometimes thankless, dangerous, and frustrating – but necessary – job. Those joining the military today have no guarantee they will be correctly used, or indeed used at all. But they shouldn't need this. Instead, all they need is a clear view of what the military is: It's the hammer to the civilian hand. It's a tool, which can be used well or ill. But the tool needs to be there, ready. That's the pride of the military, a pride that is not based on victory (over what?) or clear goal achievement. Nor is it based on a sense of superiority to the civilians it's there to protect.

I SERVED, read the bumper stickers. I was there. I stood ready. Well used or badly used, used or not used at all: Soldiers have no control over this in a democracy. That is why the civilians who control the military have to be so careful not to misuse this precious resource of sweat, muscle, intelligence, and blood.

This notion of readiness must be the basis of a new military metaphysics. It's not "hooah!" based on victory or spoils. It's more modest. But it's more sustainable. And most of all, it gives an answer to the question of why would we recommend that anyone join the military. What should we say to those who have just graduated from our academies, who are enlisting, or entering Officer Candidate School? Should we say "Congratulations"? Yes, and give the biggest cheer we can.

Bruce Fleming, a professor of English at the US Naval Academy, is the author of "Bridging the Military-Civilian Divide."