If the Senate confirms Chuck Hagel as secretary of defense, he will confront a set of challenges similar to those faced by Charles E. Wilson in 1953, James Schlesinger in 1973 and Dick Cheney in 1991. In each of those cases, recent long and costly wars were drawing to a close, and traditional enemies were disappearing or being replaced.

Those defense secretaries oversaw drawdowns in the military budget averaging 34 percent. A comparable decline is likely over the next ten years. The United States overspends on its military, and these resources could be better invested elsewhere, either through tax cuts today or deficit reduction that will ease the burden of taxes on future generations.

Hagel should start by setting the record straight on military spending. The charts make the challenge clear. Non-war spending has barely declined and will remain well above the post-Cold War average even if sequestration-level cuts go into effect. And he should neither back away from his assertion in 2011 that the Pentagon’s budget is “bloated” and “must be pared down” nor withdraw his endorsement of the Simpson-Bowles deficit-reduction plan. He should scrutinize Pentagon spending, and invite others to do the same. And he could purchase some goodwill during his confirmation hearings if he promised that the Pentagon will pass an audit.

Knowing what the taxpayers’ spend is a crucial step for any SecDef who wishes to manage the Pentagon, rather than be managed by it. Knowing why we spend it is equally vital. Americans spend far more on our military than other advanced industrial economies—both as a share of GDP and on a per capita basis—largely because policymakers in Washington have assigned the U.S. military the task of defending not just the United States and our interests, but also the territories and interests of others.

If Chuck Hagel intends to implement a responsible drawdown in Pentagon spending, he must champion conservative values of self-reliance and responsibility among America’s allies. Burden sharing is good; burden shifting is better. If other countries take on full responsibility for defending themselves, they can also do more to secure common interests, reducing the risks for American troops and costs for American taxpayers.

The Obama administration has shown little interest in letting allies bear a greater share of their defense burden. But it has consciously moved away from nation-building as a cure for terrorism. The revised strategic guidance released a year ago declared that “U.S. forces will no longer be sized to conduct large-scale, prolonged stability operations.” And, with the important exception of the ill-advised troop surge in Afghanistan in 2009, President Obama has otherwise resisted the impulse to put large numbers of U.S. troops on the ground. Hagel shares the same inclinations. When he announced Hagel’s nomination last week, the president explained, “Chuck knows that war is not an abstraction. He understands that sending young Americans to fight and bleed in the dirt and mud, that’s something we only do when it’s absolutely necessary.”

This important shift away from armed social work allows for significant reductions in the numbers of active-duty personnel in the Army and Marine Corps. Still, under current plans both forces will be larger in 2017 than they were before 2002. Meanwhile, personnel costs continue to rise. Containing these costs should be a major priority lest they strip more fighting power. Hagel—as a decorated Vietnam veteran and the first former enlisted person to hold the job of SecDef—should champion the effort to reform the compensation system and render it sustainable over the long term.

Even though they will generate smaller savings, other areas beg for Hagel’s attention and leadership. Numerous think tanks, ad hoc study groups and even members of Congress have put forward specific proposals for reducing the Pentagon’s budget. I especially recommend Carl Conetta’s latest report from the Project on Defense Alternatives.

An easy place to start is the vehicles Congress forces the military to buy even when it has enough (for example, tanks built in Ohio and destined for long-term parking in the California desert). Hagel should also consider cutting the raft of non-military activities documented in Sen. Tom Coburn’s report, “Department of Everything.”

Then there are things that the military wants but doesn’t actually need. This would include weapon systems designed for fighting unlikely wars, and legacy systems that should be superseded by new technologies. For example, the Navy should revisit its plan to build fifty-five Littoral Combat Ships (LCS), a coast-guard cutter for other nations’ coasts that has been plagued by technical and operational difficulties. The Navy should scrutinize, along with the Marine Corps, the costs versus the capabilities of the troubled F‑35, and ponder cost-effective alternatives. And it should be forced to justify the enormous expense of the next-generation ballistic missile submarine, SSBN(X). If compelled to choose between more “boomers,” more attack submarines, or more conventional surface combatants, what would the admirals pick? Hagel should ask that question. Likewise, the Air Force should be asked whether the marginal benefits that would accrue from retaining the bomber leg of the nuclear triad are worth having fewer F‑35s, fewer tankers, or fewer bombers dedicated solely to conventional strike missions. Or perhaps the Air Force should retire the other leg of the triad, the land-based ICBMs that look increasingly like relics of a bygone era?

These are the kinds of difficult but necessary trade-offs that individuals and businesses make every day when resources are constrained. The Pentagon avoided such choices during an eleven-year period, from 1998 to 2008, when its spending authority rose by 88 percent in real, inflation-adjusted dollars, including war costs. If confirmed, Hagel must bring its high-flying budget safely and responsibly back down to Earth.