In his new book, By His Own Rules: The Ambitions, Successes, and Ultimate Failures of Donald Rumsfeld, Bradley Graham argues that although ideology and arrogance played a role in the fiasco of invading and occupying Iraq, Donald Rumsfeld’s concept of transforming the military into a leaner, more deadly force also played a role.

Not only did Rumsfeld take advantage of 9/11 to justify the invasion of Iraq, but he also used it as a cudgel to attempt to transform the U.S. military. Taking advantage of a crisis to try to institute policy changes is an age-old Washington ploy. The Afghan War seemed to validate Rumsfeld’s new concept, but it wrecked on the shoals of the insurgency in Iraq.

Traditionally in wars, U.S. air power had supported U.S. ground forces. Rumsfeld believed that the improved firepower and accuracy of munitions delivered by air had made the Army less important. Now the U.S. could rely on indigenous ground forces to hold the enemy in place (being essentially an anvil), while U.S. airpower was used as a hammer to defeat opposing forces. Yet Rumsfeld did not invent this concept. During the Clinton administration, this same model was used successfully against Serbia in the war over Kosovo in 1999. The concept’s initial success after 9/11, using the ground forces of the opposition Northern Alliance against the forces of the Taliban government in Afghanistan, seemed to enshrine Rumsfeld in the military hall of fame.

Iraq was to prove the undoing of Rumsfeld’s vision, however. Again seeming to be validated was his concept of using a small number of troops on the ground to hold the enemy forces—with a more formidable Iraqi foe and no significant indigenous opposition forces to use, U.S. ground forces were substituted for the home-grown ones—so that they could be pummeled with airpower. Saddam Hussein’s forces were quickly routed and Baghdad and the rest of Iraq occupied.

And therein lies the problem with the Rumsfeld concept. Occupation is different from winning the war. Occupying a country requires many more boots on the ground, especially when a guerrilla war breaks out—as happened in Iraq. Because Rumsfeld wanted to demonstrate his new model of warfare, the U.S. always had too few troops on the ground to militarily tame the Iraqi insurgency.

What’s more, the continuing war in Afghanistan began to further erode support for Rumsfeld’s concept. With even fewer ground troops per inhabitant in Afghanistan than in Iraq, a resurgent Taliban caused an excessive reliance on airpower to fight the growing insurgency. As the U.S. military is belatedly rediscovering (the lessons of Vietnam having been long forgotten), in counterinsurgency warfare, winning at least the neutrality of indigenous peoples by not killing too many innocent civilians is more important than piling up bodies of guerrillas killed. But no matter how accurate weapons are from the air, to avoid killing civilians, eyes and boots on the ground are needed—many of them.

Bob Gates, Rumsfeld’s much more highly regarded replacement as Secretary of Defense, has scrapped Rumsfeld’s transformation program and has jumped wholeheartedly into developing forces and technology for counterinsurgency warfare.

So Rumsfeld’s vision should be regarded as the hapless failure that many have labeled it? No.

Rumsfeld’s concept is fundamentally sound if the country is fighting a conventional war against even a formidable foe. And that is the kind of future war for which the U.S. military should be planning. As a hedge against any major threat to U.S. security that might arise—none exists now—the U.S. military must be able to fight the conventional forces of a great power. Not that the Pentagon’s budget couldn’t be drastically slashed until such a threat arises, but that doesn’t mean that the military can’t have a concept about how it would fight such an enemy. And drastically cutting the number of ground forces would save many taxpayer dollars, eliminate the temptation to undertake long-term imperial missions, and ameliorate the inherent dangers that standing armies present to civil liberties and the republic.

But what about the need to reshape countries through counterinsurgencies and nation-building—as the U.S. has been attempting to do in Afghanistan and Iraq? After all, don’t we need to “drain the swamp” so that potential terrorists don’t arise from or garner safe haven in such failed states?

No, it is such imperial occupations that cause anti-U.S. terrorism in the first place—just read Osama bin Laden’s writings. To get terrorists like bin Laden we need to use improved intelligence, law enforcement, and perhaps occasional Special Forces raids. Occupation and military social work are unneeded, costly, and make the problem of blowback terrorism worse.

In short, if the U.S. gives up fighting such ill-advised wars of choice and concomitant occupations, Rumsfeld’s concept of fewer ground forces and a heavier reliance on airpower can be viable. The concept is not the problem, but it’s not going to work if the United States continues such drawn-out imperial quagmires.