The war in Iraq is over yet the Department of Defense (search) is adding more troops there, taking heat in the Senate and shuffling Iraq leadership posts. Is winning the peace really harder than winning the war?

No, it’s just different, requiring a different set of tools. And for now, it seems that an inexperienced U.S. is fumbling with its toolkit.

For the technology-intensive military that hunted and defeated Saddam Hussein's (search) forces, minimal manpower gave them speed, lessened the risk of casualties and added efficiency. A job that some Army leaders predicted would take several months and hundreds of thousands of ground troops was completed in 21 days by about 140,000 soldiers.

Once the war was over, that same amount of manpower became a liability. As the U.S. way of war has become increasingly capital intensive, the global demands of maintaining stability and keeping peace have remained maddeningly labor intensive. That leaves the U.S. military in Iraq these days in need of a new skill: How to shift from warfighting to post-war stabilization with a minimum of bumps.

Senators took Deputy Secretary of Defense Paul Wolfowitz (search) to task recently over this very issue. Waving aside the efficient military victory, they questioned whether the administration has committed enough manpower and other resources to post-war Iraq. Wolfowitz defended the U.S. mission, while calling the situation “somewhat messy.”

What would make it less so? Two things. First, greater flexibility in how U.S. forces are composed. Second, a rapid, effective method of substituting one type of force for another.

Retired Marine Col. Bob Work, now a senior defense analyst at the Center for Strategic and Budgetary Assessments, says that if the U.S. is to continue becoming engaged in military operations that carry with them an obligation to remain in the country after the war to restore order and stability, the U.S. will need the following types of forces:

Type One: A light, lethal and highly networked force with lots of robotics, continuing along the modernization path the Army is now following. This would be the warfighting force. Its soldiers would do the operational maneuvers and would come in from a distance. They’d leave the theater after they finished fighting the war — staying just long enough for the next type of force to get in.

Type Two: Similar to the Army’s current idea of a Stryker Brigade, this force would have enough strength to do crowd control and deal with marauding elements of a deposed regime and its remaining weapons. It would be highly mobile, armed with 50-caliber machine guns, heavy mortars and armored gun systems.

Type Three: This force would be for keeping order and reconstruction only, and would come in once stability had been secured. Comprised of military police, engineers, civil affairs personnel and the like, it would be equipped with light Humvees and the essential equipment needed for conducting patrols and otherwise maintaining the peace.

Iraq and Afghanistan have come in quick succession, and there’s reason to expect the U.S. military will in the future have more such engagements. Until it has rapidly deployable and varied forces, it will have to straddle the tasks of breaking things then fixing things with the personnel it currently has.

There are signs that war planners are learning on the job. Already, the U.S. is beefing up its presence in Iraq with the 1st Armored Division. And the forces look set to engage more closely with the civilians on the ground. As long as the forces in Iraq act decisively to keep order, there’s reason to expect that the security situation in Iraq will in time improve.

Traditionalists will surely chafe at the idea of devoting soldiers to mop-up jobs, arguing that the U.S. should not drain its resources on nation-building or that it’s not in the U.S. military culture to conduct such stability operations. But such arguments ignore a few salient points.

First, the job of fighting wars requires fewer and fewer soldiers: Fewer than 150,000 ground troops fought in Iraq and deposed the regime, compared to more than twice that number of troops that fought for limited aims in 1991. The declining labor-intensity of U.S. warfare frees up soldiers who can be tasked with ensuring that victories don’t get rolled back.

Second, the U.S. Army has been here before. From the Spanish-American War to about World War II, it was a “constabulary force,” tasked with protecting the frontier and keeping the peace. It was light and mobile, widely spread out, always vigilant. Now at least part of the Army must consider “going back to the constabulary model, but on a global scale rather than a continental scale,” says Work of CSBA.

The third and final reason to become good at stability operations is that there’s no point in conducting them badly. Americans may not have foreseen or intended for their soldiers to keep peace in countries where they’ve ousted a malfeasant regime. But nor did Americans foresee that 9/11 would come to pass and require the military to spend years hunting down terrorists and their willing hosts around the globe.

Given our unpleasant reality, both warfighting and stability operations are worth doing — and worth doing well.

Melana Zyla Vickers is a contributing editor to DefenseCentralStation.com.