Our civilization is under attack from a new kind of weapon: the suicide killer. Sometimes these killers explode bombs, sometimes they crash airplanes into buildings, sometimes they go on shooting rampages -- as happened at Virginia Tech on Monday.

Technology has made each individual potentially more of a menace to society, here and around the world. Not only do people have access to explosives and rapid-firing guns, but the specter of future infernal invention haunts us further. What new methods of mayhem will be concocted?

The forces of peace and order are not equipped to deal with oncoming threats. In the United States specifically, presumptions about civil liberties and the right to privacy have greatly constrained our ability to deal with possibly dangerous individuals.

On yesterday’s Today Show, Lucinda Roy, a creative writing professor at Virginia Tech, recalled her interaction with Cho Seung-Hui, the mass killer, describing him as "incredibly bizarre ... one of the most disturbed students I have ever seen." And while authorities seemed alert to the ominous implications of Cho’s behavior, they also seemed to have been thwarted from taking any intervening action.

At a press conference in Blacksburg, Va., Virginia Tech police chief Wendell Flinchum itemized a string of incidents reaching back two years in which two students had reported Cho as a stalker. And yet, Flinchum and other authorities cited the privacy provisions contained within the federal Health Insurance Portability and Accountability Act of 1996 as the reason they couldn’t act more decisively.

Did Congress and the president really intend, 11 years ago, to elevate Cho’s "right to privacy" to such an absurd level? The police chief said he was having trouble gaining access to records on the previous incidents even now. Even after Cho murdered 32 people. If not a reworking, at least a reinterpretation of the accountability law, as well as other privacy statutes, is surely needed.

Today, a tension exists between the privacy of the individual and the security of the collective. Yet, if someone in our midst has the capacity to kill a great many people, a thorough rethinking of prevention procedures is needed.

We can learn from other countries, too. Israel, for instance, confronted a wave of Palestinian suicide bombings that killed hundreds in 2002-2003. But through stern countermeasures -- including profiling, roadblocks and ultimately a wall sealing off much of the Palestinian population -- the Israelis managed to stop the killing onslaught.

Meanwhile, in Iraq, Afghanistan and Sri Lanka, suicide bombers -- perhaps better called "homicide bombers" -- are still on the rampage. In other words, countermeasures are still ineffective.

Fortunately, the United States doesn’t face the same sort of challenge at home as in the Middle East, although phrases such as "shooting spree" and "going postal" are commonly heard, for grimly good reasons.

To put it bluntly, America, with a few exceptions, is mostly one big "soft target." So if we want to protect ourselves, we need a nationwide "hardening." We must have a new architecture -- legal, physical and psychic. Take a look at each:

First, legal. Obviously, procedures for dealing with Cho-like figures need to be streamlined. If human nature in the 21st century includes more mass killers -- and sicko hoaxsters, who have been numerous in recent days -- we have to be ready for them with stern law enforcement.

Second, physical. Are public places secure? Do we need more surveillance cameras? More police? More gates and checkpoints? More sanctuary-like panic rooms? More protective walls around facilities? It’s not pleasant to think about fortresses, but it’s worse to think about more acts of terrorism.

Third, psychic. What’s the best way to react to a shooter? Run? Barricade the door? Fight back, like the "let’s roll" passengers of United Flight 93? Should more people be carrying tools for self-defense?

No civilized person wants to live in such trying times. But here we are. So we must learn new ways of protection, rededicating ourselves to the proposition that our civilization is worth defending.