With little public scrutiny, robotics is quickly revolutionizing not only how war is fought, but who fights in war.

While the U.S. military first began to experiment with remote-controlled weapons during World War I, the Pentagon had no robots on the ground when it invaded Iraq in 2003, and only a handful of unmanned aerial vehicles (UAVs) in the air. Today, the U.S. military has some 7,000 UAVs in operation -- more than double the number of manned aircraft in its arsenal -- and more than 12,000 robots on the ground in Iraq alone.

Predator drones armed with laser-guided Hellfire missiles have regularly bombed Iraq and Afghanistan and their use is skyrocketing. In 2008, 71 Predators flew 138,404 combat hours -- a 94 percent increase over the year before, according to a recent presentation by U.S. Air Force Col. Eric Mathewson. Over the last year, drones flown largely by the CIA have launched missile attacks inside Pakistan more than 40 times. Since his inauguration, President Barack Obama has authorized 11 such attacks that have collectively killed more than 145 people, many of them civilians, and sparked large protests within Pakistan.

UAVs are also increasingly being used inside the United States. The Department of Homeland Security has deployed unarmed drones to monitor the borders with Mexico and Canada. Police departments in Los Angeles, Houston and Miami have been testing drones for surveillance in their cities. Activists have reported seeing insect-sized spy drones at antiwar rallies in Washington and New York.

In Iraq, there are at least 22 different unmanned ground vehicles (UGVs) in operation. While they are used primarily for reconnaissance and to help soldiers defuse roadside bombs, the first armed ground robot was deployed south of Baghdad in May 2007.

The Special Weapons Observation Remote Direct-Action System, or SWORDS, stands three feet tall and rolls on two tank treads. It's currently fitted with an M249 machine gun that can be swapped for other powerful weapons and controlled with a modified laptop. More sophisticated UGVs -- such as the one-ton Gladiator -- are currently being developed and tested and likely will see combat soon.

Congress has helped spur this revolution. In 2001, the Defense Authorization Act stated that one-third of the military's deep-strike aircraft should be unmanned within 10 years and that one-third of ground-combat vehicles should be unmanned within 15 years. In the Defense Department's 2007 budget, Congress ordered the Pentagon to show "a preference for joint unmanned systems in acquisition programs for new systems."

Congressional backing and the increasing popularity of these systems within the military have fueled a booming robotics industry. The Association of Unmanned Vehicle Systems International, for example, has 1,400 member companies and organizations from 50 countries looking to cash in on the future of war.

In all likelihood, as proponents of military robots claim, the number of U.S. soldiers killed on the battlefield will decrease. This has been the trend with continual advances in military and medical technology and as the Pentagon has turned to mercenaries and civilian contractors who are not included in official death tolls.

For example, more than 58,000 U.S. soldiers were killed in Vietnam. Today, after six years of fighting in Iraq, fewer than 4,300 U.S. soldiers have died in combat. And in Afghanistan, about 1,100 soldiers from Western countries have been killed. The use of robots is partly responsible for this dramatic reduction in U.S. casualties. As unmanned systems are deployed in greater numbers, that figure will drop.

This may sound like a positive development, but its potential downsides are profound. At the same time that the number of soldiers killed in war has dropped, the percentage of civilian casualties has steadily risen.

In World War I, less than 10 percent of casualties were non-combatants; in World War II , the percentage of civilian casualties was roughly 50 percent. Today, over 90 percent of those killed in wars are civilians.

In Iraq, one study estimated that more than 600,000 Iraqis had been violently killed by June 2006. By allowing soldiers to kill from greater distances, which makes it easier to pull the trigger, robots may take this trend a step further.

There is already evidence that the use of aerial drones is disastrous for civilian populations. The Sunday Times of London recently reported that as many as 1 million Pakistanis have fled their homes "to escape attacks by the unmanned spy planes as well as bombings by the Pakistani army."

More than anything else, the prospect of U.S. troops dying on some far-off battlefield limits public support for military force. Therefore, if the number of soldiers coming home in body bags can be significantly reduced, then the public will probably pay even less attention to foreign policy and future wars. This will make it easier for politicians to start wars.

John Pike, the director of GlobalSecurity.org, recently wrote that robots would allow the United States to intervene militarily in Darfur or other hot spots where politicians are currently reluctant to send flesh-and-blood soldiers.

Robots will reduce the need for recruitment, too. Whereas each SWORDS is controlled by at least one soldier, progress in the field of artificial intelligence may allow a soldier to control multiple robots simultaneously.

James Canton, an expert on military technology, predicts that future military units may consist of 150 humans and 2,000 robots. This would allow the government to go to war with far fewer humans.

Robots will also ease the physical fitness and age restrictions for new military recruits. As Noah Shachtman, editor of Wired's Danger Room blog, has said, "having a strong bladder and a big butt may be more useful physical attributes" for future soldiers than being able to do a hundred push-ups.

While a robotized military presents new challenges for antiwar activists, it also creates new organizing opportunities. Many weapons builders that develop unmanned systems, such as iRobot and Northrop Grumman, are publicly traded companies. That exposes them to potential shareholder resolutions and makes them more sensitive about their public image.

Some military contractors also make consumer products. For example, iRobot manufactures both the PackBot, a bomb-disposal robot that can be armed with a shotgun, and the popular Roomba vacuum cleaner. As the market for personal and service robots -- valued at $3 billion in 2008 -- continues to grow, boycotting corporations that make both consumer and military robots is potentially an effective tactic for activists.

With nearly 350 colleges and universities reportedly conducting research for the Pentagon, another possible target is robotics research funded by the Department of Defense.

On March 2, 2007, activists with the Pittsburgh Organizing Group blockaded Carnegie Mellon University's National Robotics Engineering Center in Lawrenceville. CMU is one of the largest academic military contractors in the country. Fourteen activists were arrested during the protest, which shut down the robotics lab for the day and garnered considerable media attention.

Finally, activists are beginning to protest at military bases where the drone pilots work. At Nevada's Creech Air Force Base -- one of the locations where controllers use Predator and Reaper drones to bomb Iraq, Afghanistan and Pakistan -- protesters who participated in the Nevada Desert Experience's annual Sacred Peace Walk kept a presence outside of the base for 10 days, and 14 were arrested in an act of civil disobedience on April 9.

When it comes to killer robots, the stakes are high. If activists don't work to stop this robotics revolution in its tracks, science fiction has warned us about our potential fate.