By the time you read this, I should be filthy rich.

I recently received an e-mail that claimed to be from a high-ranking Nigerian official who had discovered some funds stolen by Nigeria's former military government. The bank account holding this money, I read, could be used only to transfer the funds abroad. All I needed to do was respond with the name of my bank, my bank account number and some personal information. In return, "Dr. Ahmed" would wire me 35 percent of the trapped $41 million.

Of course, this junk e-mail was nothing more than an invitation to be swindled. With my bank information, the good doctor could clean out my savings, wiring the money through a series of other accounts so that I would never see it again.

Like me, you probably delete dubious electronic missives like this one without much thought. But apparently, not everyone is so skeptical. Last year, the Nigerian banking swindle made number three on the National Consumers League's top-10 list of Internet scams. The Federal Trade Commission says that Americans are losing more than $100 million a year to international con artists. But things could be much worse: most of the Nigerian scam letters sent through paper mail get stopped and destroyed at the border by the U.S. Postal Service-ironically, because they are sent with counterfeit stamps.

But while the government vigilantly patrols our physical borders, it is doing precious little to control our electronic ones. Consider this: someone trying to bring fresh fruit from Europe into the United States will be stopped by an agent of the U.S. Department of Agriculture. But there's nothing to protect you from the electronic damage wrought by an infected Microsoft Word file sent to you by some computer hacker in Iraq. Many scholars and civil libertarians say that this is as it should be: while controls on physical borders involve the movement of mere people and things, electronic-border control would regulate information and ideas. Any attempt to block the importation of ideas would be, by definition, an exercise of state censorship. And that, many believe, is a no-no.