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It would take a few more years after the Iraq invasion for the military to learn—and promote the officers who figured out through experience—the rough balance of forces, and the kind of training, needed both to fight the first phase of the war and to achieve the objectives in the aftermath.
This evolution set in motion three big changes:
First, the basic Army unit has been scaled back from a division (about 12,000 soldiers) to a more agile brigade combat team (about 4,000)—and in some operations, to a battalion (one-third of a brigade). To his credit, Rumsfeld initiated this process, though his motive was to slash the size of the Army overall, which may have been a good idea but not if he was preparing to invade Iraq.
Second, some Army specialties are more important than they used to be, and some are less. Field artillery officers, for instance, haven't been firing artillery for quite a while. Tank officers, too, are underemployed. Tanks have played almost no role in our present wars since the invasion of Iraq. At the same time, soldiers specializing in light infantry, airborne assault (helicopters), special operations, and civil affairs have had more to do than at any time in decades.
Third, the Air Force—whose main purpose, in the latter half of the 20th century, was to bomb targets deep inside the Soviet Union and to engage in air-to-air combat with enemy fighter planes—has, to an extraordinary extent, reverted to its original role (before it became an independent service in 1947) of supporting the Army.
For more than a year, the Air Force has been training more "joystick" drone pilots than actual airplane pilots. These joystick pilots don't sit behind the wheel in a cockpit; they sit in a base in Nevada, maneuvering an unmanned aerial vehicle via remote control, watching the live video that the camera on the UAV's belly is streaming back to the base, and firing a weapon against an enemy target when so ordered.
The UAV pilots are, in fact, the new elite of the Air Force. Think about it. If you're the pilot of an F-15 or F-22 jet fighter, you have a lot of fun: Those planes go fast and turn tight. But the United States is involved in at least three wars now, and those planes are barely involved in any of them. (The F-22 hasn't made an appearance in any war since it rolled off the production line.) By contrast, the joystick pilots are in the action every minute they're on duty; they're in constant contact with soldiers on the ground and with intelligence officers analyzing the video stream. They are in the war every bit as much as a fighter, bomber, or reconnaissance pilot was in wars of the past.
Some officers and analysts sound an alarm bell over these changes. As military personnel learn new skills and adapt to new forms of warfare, are they un-learning old skills, which might be essential if the old forms of warfare stage a comeback? Artillery and advanced air-to-air jet fighters aren't so important now, but they might be if a large power invades or starts bombing an ally.
But the Air Force still has a lot of air-to-air fighters and pilots, and the Army has adopted a strategy called "full-spectrum operations," in which soldiers are trained and equipped to pivot on a dime from head-on combat to stability operations to counterinsurgency. (The Marines have long subscribed to a doctrine of "the three-block war," an idea, coined by Gen. Charles Krulak in the late 1990s, that, over a span of three city blocks, a Marine might be called upon to fight full-scale combat, then conduct peacekeeping operations, then provide humanitarian aid.) *
This sounds good, but is it feasible? Not all athletes are pentathletes. Can all soldiers be full-spectrum operators? Can all Marines be three-block warriors?
For now, smart bombs can pretty much do what artillery once did; Air-to-air dogfights do look like a relic of the past; and we do seem to have a military that, over the past decade, has become more adept at staying flexible, learning lessons, and adapting to new situations. This says nothing about the wisdom of the policies they're ordered to defend, or the likelihood that they'll succeed in a given conflict. But it does suggest the force is more capable now than it was 10 years ago of doing what a military is supposed to do.
Correction, Sept. 2, 2011: This article originally misidentified Gen. Charles Krulak as a major general. (Return to the corrected sentence.)