Last week, Defense Secretary Robert Gates called for slashing military spending. That’s the impression you’d get from conservative wailing about Gates’s speech, anyway. But what the administration has proposed is only a “cut” in Washington-speak: budget growth that’s slower than those feeding at the trough would like.

Even so, such a “cut” is something new for the Department of Defense (DOD). Over the last decade, the Pentagon’s budget has grown by nearly 50 percent, even excluding the costs of our two ongoing wars. A defense budget that actually aimed at defense would make genuine, and deep, cuts in military spending.

Call for seriously downsizing DOD, and people tend to sniff at you like you reek of patchouli. Our stale defense policy debate only has room for two teams: hippies or hawks. Would you like to buy the world a Coke, or would you rather cow it into submission?

Fortunately, there’s another option. Two of our better presidents pointed the way in their farewell addresses. George Washington condemned permanent alliances abroad, and Dwight Eisenhower warned against “mortgag[ing] the material assets of our grandchildren” to the “military-industrial complex.”

In an important new book, The Power Problem, Christopher Preble defies the conventional categories and gives us a 21st-century foreign policy consistent with American traditions. (Full disclosure: Preble is a friend and a colleague).

Preble argues that our current defense posture is radically out of line with American interests, properly understood. He calls for scrapping our outdated Cold War alliances, and insists that the constitutional goal of “the common defense of the United States” could be secured by a military budget far smaller than what we currently spend.

Today, America accounts for almost half of the world’s military spending; add what our European allies spend, and you get to over two-thirds. Yet both Democrats and Republicans remain convinced that we need to keep spending more.

Gates’s proposed slowdown has provoked a fight between Pentagon players who want to bulk up for conventional wars and those who think the US military needs to get serious about nationbuilding. But we’d be better served doing less of both.

We face no serious conventional threat abroad, nor do we need to fight continual counterinsurgencies to protect ourselves from terrorism. We can’t remake every “failed state” the world over, and even if we could, terrorists would still be able to operate in places like Hamburg, Germany, where Mohammed Atta prepared for the 9/11 attacks. Gates is right that high-tech geegaws like the Army’s Future Combat Systems do little to protect us from terrorists. But neither does the expansion of the Army and the Marines that Gates endorses.

Preble makes the counterintuitive claim that our military dominance actually makes us less safe. It encourages free-riding by our allies and makes it too easy for us to fall into the role of world policeman. Little wonder, then, that in the 15 years since the fall of the Berlin Wall, we’ve intervened abroad more than we did in the 45 years of the Cold War.

John Quincy Adams famously warned against going abroad “in search of monsters to destroy.” Refusing to heed that warning, we’ve empowered new monsters. Paul Wolfowitz, no peacenik he, has admitted that the stationing of U.S. forces in Saudi Arabia was “Osama bin Laden’s principal recruiting device.” The Pentagon’s think tank, the Defense Science Board, says that our foreign occupations have “elevated the authority of the Jihadi insurgents and tended to ratify their legitimacy among Muslims.”

Preble ends The Power Problem with a quote from Jefferson, who, after we beat back the British in the War of 1812, envisioned a day when America might “shake a rod over the heads of all.” But the Declaration’s author hoped that “our wisdom will grow with our power, and teach us, that the less we use our power, the greater it may be.”

Congressional Republicans recently introduced an alternative budget that freezes most discretionary spending, but gives the military a free pass. The GOP is right to resist Obama’s drive toward Eurosocialism. But they’d have much more credibility if they put DoD on the chopping block as well. In an era of limits, the bloated defense budget shouldn’t be off-limits.