Late in February, U.S. Army generals in Iraq started asking military historians and archivists to dig up official records from the 1970s involving the withdrawal of troops from Vietnam. The generals were especially interested in the nitty-gritty of pulling out—procedures for disposing and transferring military property, for example, and the precise sequence of demobilization. The message was explicit: we’re going to be staging another withdrawal soon, from Iraq; once it begins, it could spin easily out of control; so we need a plan for an orderly exit now.

And yet, in three years of occupation, the U.S. military has taken steps that suggest a total pullout is unlikely for years to come. The most tangible sign of these measures is the far-flung network of Forward Operating Bases, or FOBs. There are more than seventy FOBs scattered across Iraq, many of them elaborate renovations of Saddam Hussein’s former network of military bases and presidential palaces. Some FOBs consist of just a handful of barracks, but more than a dozen of them are vast complexes reminiscent of the West German garrisons from Cold War days.

The larger bases are fortified chunks of Middle America, surreally plunked down in the desert, replete with Burger Kings, Pizza Huts, Internet cafés, first-run movie theaters, gyms, and swimming pools. Camp Anaconda, built around two 11,000-foot runways and spread out over fifteen square miles, is home and workplace to 20,000 U.S. troops and 2,500 private contractors. Camp Cooke, which boasts 29,000 square feet of retail shopping, is so huge that a shuttle bus runs back and forth from one end to the other. At Camp Falcon, Army engineers had to bring in 100,000 tons of gravel just to build the reinforced roads.

There’s nothing provisional about these places. They’re often referred to as “enduring bases,” and there are plans to keep them operating, in American hands, even if all our combat regiments go home. The Pentagon is requesting $348 million in emergency funds this year for further base construction, beyond the billions already spent.

And so we are operating in an odd state of limbo. It’s clear that we’re getting out of Iraq, and soon, yet it’s equally clear that we’re staying, in a fairly big way. We are simultaneously engaged yet disengaging, hunkered down yet packing up.

Here’s the little secret that explains the contradiction, understood by all involved: whatever factions end up running the Iraqi government, they’ll need—and want—the U.S. military to stick around for many years. This is true no matter what the political mood is stateside.

Over the past year or so—ever since competent American officers were finally put in charge of training local soldiers—the Iraqi army has been growing and improving. Yet the Pentagon estimates that while nearly half of the Iraqi units are able to lead a combat operation, not one can fight by itself. The reasons are plain: the Iraqi military has no air force, no centralized intelligence corps, scant logistics apparatus, and only one armored battalion. As a result, it is—and, for the foreseeable future, will be—unable to coordinate a battle plan, defend the country’s borders, provide air support, or protect supply lines. To perform any of these basic tasks, it will need an outside power with professional armed forces. And unless some other country gets involved soon, that outside power will have to be the United States.

Strategy is an art, logistics a science; and the U.S. military has always been extremely adept at science. To supply an army with bullets, bombs, bandages, spare parts, repair kits, fuel, food, water—and to keep all these things moving through the system so nobody runs short—requires extensive planning. For each American soldier capable of going out on patrol or fighting insurgents, there are five support troops supplying his needs, according to an Army spokesman. In other words, of the roughly 130,000 American troops in Iraq today, only about 25,000 are combat troops. Categories overlap, of course; a truck driver in a convoy can find himself in a firefight or be hit by a roadside bomb. Still, when the generals plan how many troops they need, this is the combat-to-support—or “tooth-to-tail”—ratio that shapes their calculations.

Once the Iraqi army stands up and our combat troops stand down—as President Bush puts it—U.S. military planners estimate that the Iraqis will still need 20,000 to 30,000 Americans for logistics, air support, intelligence, and so forth.