Imagine Saddam Hussein sitting in one of his palaces, tapping on his laptop, maybe shopping at Uranium Online.

Which actually exists, by the way. Tag line: "The nuclear fuel e-commerce solution."

All of a sudden, Saddam's computer explodes with e-mail. It's all spam, made in America thousands of offers. Consolidate your debt. Earn money working at home. Enlarge your breasts.

It would be like Internet carpet bombing. He'd surrender within days.

In reality, the U.S. military is developing cyberwarfare weapons. Details of the program are top secret. OK, it probably doesn't involve unleashing spammers on Iraq, but you never know.

Whatever the plan, the concept of cyberwar brings up a whole boatload of questions. No nation has ever used Internet technology to launch a military cyberassault. Cyberattacks would be one of those technological firsts that changes the nature of war, historians say. In that sense, it could have an effect like the longbow, a technological advantage that helped the English whip the French, albeit slowly, in the Hundred Years War.

Although, cyberwar could be more like the first nuclear bombs in one important sense: As with the first nukes, no one knows what might happen if cyberwar is unleashed. It could backfire and result in rapacious attacks on U.S. computer systems. So the United States seems to be thinking hard about whether and how it would use this new weapon.

Of course, cyberwar doesn't involve a better way to kill people or blow things up, which is a welcome divergence from the history of new weapons. As unknowns go, it's not nearly as frightening as biowarfare. Still, its impact could be great.

"The danger from computer warfare is very real," says Amir Aczel, author of books such as The Riddle of the Compass, about significant technologies of the past.

Under U.S. Strategic Command in the Pentagon is a unit called Joint Task Force-Computer Network Operations. In military parlance, it's the JTF-CNO, or just the CNO. Under the CNO comes the CND (Computer Network Defense) and the CNA (Computer Network Attack). All are extremely secretive. You won't see the CNO, CND or CNA on CNN.

The CND addresses familiar concerns: preventing enemy hackers from breaking into vital U.S. computer systems or disrupting the Internet. Its mission is protection, similar to building a wall around a medieval city to keep out the Goths.

The newer CNA, created in 2000, is working on offensive Internet weapons. If we attack Iraq, for instance, soldiers armed with PCs might fire hacker software bullets over the Net to shut down Iraq's electrical grid or overwhelm computers in Saddam's headquarters. The military might even get creative, sending code that launches a RealNetworks player on every Iraqi PC, then shows a digitally altered video of Saddam instructing everyone to surrender.

The Bush administration remains opaque about what it can or might do. "We have capabilities, we have organizations, we do not yet have an elaborated strategy, doctrine, procedures," said Richard Clarke, after he resigned earlier this month as special adviser to the president on cyberspace security.

What happens, though, if we launch a cyberassault? You might expect some al-Qaeda cells to retaliate. Such Internet terrorists could do some damage. Remember, the network-clogging "I love you" virus was launched in 2000 by a group of unspectacular students from a Filipino trade school. Al-Qaeda could no doubt do better.

Yet, enemy hackers attack us all the time anyway, provoked or not. They're relative amateurs. After NATO began bombing Serbia in 1999, Serbian-sympathizing hackers from all over the world attacked more than 100 businesses in NATO nations. It had less impact on daily life than a broken traffic light. Hackers constantly try to break into computers at the Department of Defense, the CIA and the Department of Energy. As far as anyone has told the public, the damage has been minimal.

The scarier scenario, officials point out, is legitimizing cyberwar. If the U.S. military makes it a part of war, other nations will, too.

Hackers are one thing. A coordinated cyberassault by another nation is something else. Last year, Air Force General Ralph Eberhart told reporters that China is developing cyberwarfare capabilities, and he was pretty darn concerned. There's more chance such an attack could shut down or clog not only military computers, but financial networks and other systems that run the U.S. economy.

"God help us if any of these people get to the computers that control nuclear power plants a thought that makes me shudder," author Aczel says.

"Cyberwarfare could in fact be the tool that allows weaker nations to offset America's military might," Northrop Grumman CEO Kent Kresa said in a speech about cyberwar.

The problem is that the United States is more reliant on computers and the Internet than any other nation. If we trade cybervolleys with another country, we're more likely to suffer greater damage. In the USA, the simplest acts heating your house, writing a work memo, calling your mom rely on computer networks. Most of us could no more live life without computers than we could make our own butter. We're such a fat, vulnerable target.

So we need to be careful.

Especially if we use the spam strategy. Iraqis could wind up on all those mass e-mail lists after the war. The Iraqi people would never forgive us.