From the time a soldier wakes up until it's time to sleep, he or she interacts with civilian contractors. Much of the focus has been on " personal security detachments," or PSDs — the bodyguards, like Blackwater.

But by some estimates, there are as many as 180,000 contractors, and PSDs make up a small fraction. The majority of the jobs are service support for the troops and are filled by non-Americans. The effect of these civilians in the Iraq war has yet to be fully examined, and the legacy of their role will affect how our nation fights future wars.

The trash being sifted and sorted out of a soldier's garbage bin is conducted by civilians working for Toifor Co. When soldiers walk to the morale, welfare and recreation facilities, they are greeted by more civilians who run the gym. Outside the gym, civilians are stacking up bottled water.

When a soldier turns in laundry, it is to an East Asian civilian who prides himself on his English and customer service. The soldier has the luxury of a hot shower because Indonesian civilians ensure a ready supply of water.

At the dining facility, soldiers are greeted by Ugandan security guards who work for EOD Technology. These Ugandans make roughly $1,000 a month, meager by U.S. standards but considered a small fortune in their country. They also provide security at the forward operating bases — the largest camps — because there is not enough U.S. military to do so.

While preparing for a mission, a soldier can expect technicians from General Dynamics or other major defense contracting companies to aid Army soldiers in the upkeep and maintenance of essential equipment. The Iraqi interpreters work for a contractor, probably Titan Corp. In addition, many Filipino drivers are responsible for ensuring that heavy equipment — such as Humvees and Strykers — reach their destinations after they're unloaded in Kuwait.

On returning from a mission, a soldier will interact with many civilians hired by KBR, which runs the general support services for the base. Many of these workers are Serbs and Croats who have been employed by the company since the Clinton administration, when the United States held a significant role in the peacekeeping operation in Serbia.

The majority of all this civilian activity usually goes unnoticed on the bases by soldiers and even more so by U.S. taxpayers, who generally think their taxes support only the military forces.

After the Vietnam War, many of the combat-support duties were transferred from full-time soldiers to U.S. National Guard and Reserve units. But today that structure has been undercut as civilians have taken over those jobs. And these civilian contractors in the non-security roles are only a degree away from what we historically have called mercenaries. They may not be carrying weapons, but they nonetheless assist, equip, sustain and maintain the military forces in Iraq.

This war has demonstrated that there are not enough soldiers to equip and sustain a deployed force continuously for multiple years and deployments. Although the Defense Department has not released any official count on the total number of contractors, some reports have indicated that contractors outnumber soldiers.

The revolution in military affairs envisaged by Donald H. Rumsfeld early in his tenure as secretary of Defense has occurred. The military can deploy with fewer soldiers and still achieve the administration's goals. Implicit in this revolution, though, is the reality that civilian contractors have come to take a significant, vital and cloaked role in the country's prosecution of a war in which Americans are fooled by the actual numbers required to carry out a war.

The Romans found mercenaries to be a quick-fix solution. However, a temporary fix became a permanent force that the Romans used when they found their own legions had become too expensive — economically and politically.

Let us hope that the United States does not follow the fate of the Roman Empire in this regard.

Timothy K. Hsia is an Army infantry captain on his second deployment to Iraq. He wrote this commentary for the Los Angeles Times.