The supercommittee's failure to come up with a debt-reduction plan last week wasn't a surprise, and I'm not mourning the outcome. Frankly, I started rooting for failure a couple of weeks ago, as I listened to a talk by Bill Hartung, an expert on US military spending.

Hartung (a senior research fellow at the New America Foundation's American Strategy Program) isn't the only one who saw advantages in a committee deadlock. But Hartung makes a particularly important point. Failure - and the legislated threat it creates to the defense budget - gives us a chance to do something crucial: think about what kind of defense the nation really needs today.

Hartung notes that budget appropriations for the Pentagon have been going up steadily, rising 73 percent from 2001 to 2009. And, he wrote in a December 2009 article for Foreign Policy in Focus, "that's not even counting the over $1 trillion in taxpayer money that has been thrown at the wars in Iraq and Afghanistan."

"We have," he wrote, "a permanent war budget, and most of it isn't even being used to fight wars - it's mostly a giveaway to the Pentagon and its favorite contractors."

The defense industry is one of the most powerful of the special interests working the halls of Congress. And many of the industry's lobbyists, Hartung notes, formerly served on the staff of key members of Congress, giving them unique access and influence.

Nor is it news that to many politicians, the defense budget is sacred - not so much for national security as for the jobs it provides in their district. Members of Congress have fought to maintain programs that military leaders themselves don't want.

We see the result: We have more nuclear weapons than we need. More overseas bases than we need. "The United States has 12 aircraft carrier task forces," Hartung said in a recent e-mail, "while no other country has even one aircraft carrier even remotely as large or capable as ours. China is working on one, but it is a smaller, refurbished version of a former Soviet ship."

The US spends "almost as much on its military as the entire rest of the world combined," Hartung noted in a June 2010 article for The Nation. Our Navy, he wrote, "is larger than the next 13 navies combined."

"Real reductions" in military spending, Hartung warned in the Nation article, will require more than just eliminating fraud and cutting weapons programs. "It will mean cutting back on the missions the military is expected to carry out," he wrote. We'll have to reduce the number of military bases and the number of troops we have stationed overseas. And, he said: "There should be no more Iraq-style wars of occupation, and no plans to undertake them."

"No longer should it be assumed that US forces should be able to go anywhere and fight any battle," he said.

"We have to think about what the military is for," Hartung says. "Some of the debate makes it sound like we need exactly the forces we have now, no matter what the problem."

How much defense do we need? What kind? Under what circumstances should we use our military power?

We ought to spend the next months dealing with those kinds of questions. But the lobbying, the campaign contributions, the emotional appeal of the word "defense": all combine to protect and grow the defense budget. To override all that will take a public that is willing to both listen and learn, willing to shut out the rhetoric and think this through. Do we have that in us?

Maybe the supercommittee's big failure will be a test. We now have a unique chance to take a hard look at government spending - and discuss whether we want to invest in excess militarism or in education, health care, jobs, and infrastructure.

Whether we seize that chance is another matter.