Honey, I Shrank the Pentagon LET'S imagine you are the new secretary of defense, and, wow, has Secretary Panetta left you a full docket. You have to extract more than 60,000 troops from Afghanistan without leaving behind a Mad Max dystopia. You have to carry on shadow wars against homicidal extremists, refine contingency plans for Syria and Iran, keep an eye on China's pushiness and Pakistan's fragility, all without being too distracted by the frat-house antics of hormonal generals. It's easy to overlook in all that excitement, but your best opportunity to make a major contribution to the security of your country is none of the above. It is the unglamorous, unpopular, unfinished business of right-sizing our defense budget, without putting us at grave risk. What's that you say? You'd rather go back to reading General Petraeus's flirty e-mails? I sympathize. Imagine trying to get people to read a column about the budget. Yet here you are with a historic opportunity to push the "Refresh" button on our national security. One long ground war is over, another is ending, and there is no prospect of (or stomach for) new wars of occupation. No new cosmic threat has arisen, much as hawks have tried to promote China, our biggest lender and one of our biggest trading partners, into that role. And, to cap it all, your budget is headed for that dread fiscal cliff. In the absence of a budget bargain between Congress and the president, half of the automatic spending cuts that take effect in January will come from your domain - almost 10 percent applied evenly across all accounts. This is widely viewed with alarm by military experts in both parties who see it, rightly, as budgeting by meat ax. So, then, what's the alternative? This country accounts for more than 40 percent of the money spent on defense worldwide. We spend as much as the next 14 countries on the top-spender list, combined, and most of them are American allies. And that's just the Defense Department. It doesn't include the Energy Department's nuclear weapons program, the C.I.A."s drone franchise, the NASA satellites, the benefits provided by Veterans Affairs, and so on. For defense conservatives, reinforced by members of Congress whose constituents build ships and aircraft, there is no such thing as enough. The determination to maintain our commanding position in a dangerous world is inflated by the clout of arms makers and sanctified by our civilian reflex to call everyone in uniform "hero." No one who actually wears a uniform does that. For liberals, the defense budget is invariably too much, a deep aquifer of wealth that should be tapped to quench our domestic thirsts. When liberals are in power, though, they tend to recoil from serious cost-cutting, partly for fear of seeming weak, partly because no one wants to be picketed by the shipbuilders" union, but largely because, from where a commander in chief sits, the world is a genuinely scary place. In his re-election campaign, President Obama was largely silent on military spending, except for his sarcastic retort about bayonets and horses when Mitt Romney complained that we have fewer battleships than we used to. But the economic crisis has chipped away at Defense's defenses. Early this year, in conformity with a budget directive from Congress, Panetta proposed a budget that would cut $487 billion - about 8 percent - from planned defense spending over 10 years. The fiscal cliff, known to defense wonks as "sequestration," would cut an additional $492 billion. Most of the experts I follow think defense can be safely cut below Panetta's level. How much? David Barno, a retired Army lieutenant general, and his colleagues at the Center for a New American Security last year laid out four increasingly severe budget-cutting scenarios in a very readable and, to my mind, credible report called "Hard Choices: Responsible Defense in an Age of Austerity." Barno told me he could live with the second option ("Constrained Global Presence"), which cuts between $150 billion and $200 billion deeper than Panetta over 10 years. Barno estimates that additional "tens of billions, conservatively" could be saved by tightening the generous health and retirement benefits for military personnel and reforming the way we acquire new weapons. The bipartisan Simpson-Bowles fiscal commission recommended cuts in the same range. A new report from a defense panel assembled by the Stimson Center says that if the military is given flexibility to apportion the cuts where they will do the least harm, we can cut $550 billion - about the same amount as sequestration - "with acceptable levels of risk." The centrist think tank Third Way recommends the same. These people are not reckless anti-military types or Ron Paul isolationists. None of these cuts would absolve us of the need to grapple with the unsustainable growth of entitlements and to raise tax revenues. But making defense pay its share would make those other economies less painful. And after all, as Adm. Mike Mullen, former chairman of the Joint Chiefs, was fond of saying, "The single biggest threat to our national security is our debt."