Protecting the nation from a potentially devastating cyberattack is not easy. The technological challenges are considerable - even major technology companies have trouble defending themselves against hackers. The number of potential targets is enormous. And because many of the targets are in private hands, the Department of Homeland Security has to work with entities that may be reluctant to follow the government's lead.

But overcoming these obstacles should be a high priority. One of the lessons of the Sept. 11 attacks in New York and Washington was how much damage a few men with simple weapons, like box cutters, could do if they targeted a point of maximum vulnerability. In a well-planned cyberattack, a single terrorist with nothing more than a computer and Internet access could do an extraordinary amount of harm from half a world away.