Let's debate futuristic weapons while we still have time

The confluence of computer science, robotics and communication advances has led to developments in defense technology that were science fiction only a few decades ago.

These developments fall into four basic categories:

• Stealth — These techniques are primarily designed to reduce radar visibility, although they also apply to the full electromagnetic spectrum, including visible light, infrared and sound. The best known examples are the F-117 fighter and the B-2 bomber. Today, the military is applying advanced stealth techniques to almost anything that moves, including ships, ground vehicles and humans.

• Unmanned vehicles — This category includes aircraft (UAV), ground vehicles (UGV) and undersea craft. The most famous examples are probably the Predator and Reaper "drones" used to assassinate terrorist leaders in Afghanistan, Pakistan and other areas. Most drones are designed for aerial surveillance and include vehicles such as the Global Hawk, a high-altitude, long-range successor to the U-2. At the opposite extreme are small, hand-launched UAVs used by ground troops at the squad level. UGVs entered service primarily in explosives disposal, but they have rapidly assumed other roles such as sentry and forward observer duty. It is estimated that UAVs make up more than 40 percent of all U.S. military aircraft and that there are now more than 15,000 UGVs in service.

• Directed energy — Truly the stuff of "Star Wars," these techniques use lasers, high-frequency sound and energy bursts to disrupt or damage opposing military equipment.

• Cyberwarfare — It is not clear yet whether software can serve as a weapon in the traditional sense, but it is clear that cybertools will increasingly be used to augment and enhance other weapons systems.

There is no doubt that these high-tech weapons are exciting and have a "Wow!" factor that engages the general public.

• Cost — Current U.S. defense spending nearly equals that of the rest of the world combined. Can we afford the continued acquisition of these new technologies? With rising military spending in China, can we afford not to?

• Adaptability — The introduction of new technology in the military has always met resistance. It took horse cavalry officers decades to accept that tanks had made them obsolete. The U.S. military-industrial complex carries significant inertia. For example, despite the proven effectiveness of drones, there is a pilot culture that strongly resists the idea of pilotless attack planes and fighters. The most advanced and expensive defense project in history is the F-35 Joint Strike Fighter, which still requires a human pilot. Will the U.S. military be nimble enough to adapt as quickly as other states or nonstate adversaries?

• Legal and ethical issues — The United States does not publish figures on the deaths caused by drones. However, it is estimated that more than 4,500 people have been killed in U.S. drone attacks and that more than 50 percent of those victims have been nonmilitants. The U.N. Special Rapporteur on extrajudicial executions has stated that the United States may be in violation of international human rights law. And many critics find the administration's justification for these killings unconvincing. These attacks are extremely unpopular in the targeted countries.

Are we killing militants and simultaneously helping to create the next generation of terrorists? The issues may become more complex as UAVs and UGVs are given more autonomy to actually fire weapons. Military leaders routinely repeat the mantra that "a human will always be in the loop." But will this be true once the military has such capability in hand?

Historically, the specter of combat deaths has served as a major deterrent to the United States' becoming involved in military conflict. As machines remove humans from the more dangerous roles of warfare, will the United States be more likely to enter conflicts?