Greg Jaffe, the Wall Street Journal’s ace defense correspondent, had another one of his riveting articles on the front page Thursday: “At Lonely Iraq Outpost, GI’s Stay as Hope Fades.” It tells the story of a small group of soldiers manning a lonely outpost in the town of Tarmiyah in Salahuddin province about 30 miles north of Baghdad.

This town of 30,000 had been relatively stable until last year. But in summer 2006, an Iraqi army battalion stationed there was pulled away to police Baghdad, and the Shiite campaign of ethnic cleansing in the capital pushed some 6,000 to 10,000 angry Sunnis northward. Tarmiyah became an al-Qaeda stronghold, where even the local police chief feared to walk the streets.

The 50 U.S. soldiers stationed there feel under siege, and for good reason. Writes Jaffe: “In mid-February a massive truck bomb sheared off the front of the soldiers’ base in Tarmiyah, sending concrete and glass flying through the air like daggers. The soldiers at the small outpost spent the next four hours fighting for their lives against a force of 70 to 80 insurgents.”

The story of the attack is as harrowing as its aftermath is inspiring. Most of the soldiers wounded in the attack—including a sergeant whose “back and neck were peppered with glass” and a lieutenant who has become “virtually deaf in one and ear and seems to have limited hearing in the other one”—volunteered to return to Tarmiyah. One sergeant explained his decision as follows: “I have a strong bond with this platoon. I don’t want to leave.” That’s typical of soldiers in this or any other war—they fight for their buddies more than for any lofty ideals.

Yet, while the story provides plenty of cause to celebrate the soldiers’ valor and dedication, it might, on the surface, also provide more fodder for those who question what good our troops are doing in Iraq. Many of the soldiers quoted in the article wonder, understandably, if they’re having any impact. It’s easy to imagine that many readers of Jaffe’s article would also wonder what the point of the Baghdad security plan is if it simply pushes insurgents a few miles away. The experience of Tarmiyah would seem to support Senator Joe Biden’s balloon metaphor: “Essentially, when we squeeze the water balloon in one place, it bulges somewhere else.”

Actually, the right metaphor here is not the bulging balloon but the spreading oil spot. That’s the classic counter-insurgency strategy, invented by French generals in the 19th century, which holds that it is best to expand one’s sphere of control slowly rather than trying to pacify an entire country at once. Concentrate your forces at first in a few areas, clear them out; once they are secure, move on to the surrounding areas. That’s not a strategy we’ve followed in Iraq until now. Instead of trying to achieve critical mass in a few places, we’ve spread an inadequate number of troops thinly across many provinces, making it hard to achieve much stability anywhere.

The new Baghdad security plan represents a change of strategy. Under it, we will put more troops into the capital in the hope of pacifying it. Some of the newly deployed troops are being diverted to the areas around the capital—the “Baghdad belt”—but not in the hope of pacifying them. They are on an “economy of force” mission to disrupt insurgent strongholds and make it more difficult to carry out spectacular terrorist attacks in Baghdad.

That’s what the troops in Tarmiyah are up to. It can be frustrating to the soldiers involved, but it’s the right strategy, given our limited resources. If General David Petraeus and Lieutenant General Ray Odierno send too many reinforcements to places like Tarmiyah, we will have no hope of achieving critical mass where it counts—Baghdad. If we ever succeed in calming the capital, then we can worry about the hinterlands.