The key to guarding against terrorism lies in making vigilant, not blind, choices of whom to monitor and how.
It is a scene we have seen in many old movies. A jackbooted officer in a high-peaked cap snarls at frightened train passengers: “Your papers, please.”
There is no doubt where our sympathies lie. Americans don't bear authority easily, even when we are worried about sinister forces like suicide bombers.
So it is hardly surprising that the recent decision to conduct random searches of backpacks and packages carried by passengers on New York and Boston subways, commuter trains and buses has provoked controversy. Americans want better security, but remain wary about how it is provided.
Obviously, such searches raise troublesome privacy issues. But some surrender of privacy seems necessary to promote security against terrorism.
We prefer security to be passive and egalitarian. We don't mind showing a photo ID at an airline counter, but find it intrusive if the airline cross-checks the data on our passenger record with other data from government files or credit-card records. We don't mind walking through metal detectors, but consider someone looking through our backpack intrusive.
We bridle at selective scrutiny — the idea that some may be cut out of the herd for interrogation or inspection is an affront. We feel more comfortable when everyone goes through exactly the same procedures, even though this mindless mechanical repetition is not the most effective way of providing protection.
There is very little that security can do to stop terrorists determined to kill indiscriminately and ready to forfeit their lives. But that doesn't mean security is worthless any more than the persistence of crime argues for the abolition of laws and the police.
Following the bombings in London, transportation operators around the world deployed more police and explosives-sniffing dogs, contemplated increased security camera coverage and admonished the public to be more vigilant. Prompted by the Irish Republican Army's 25-year terrorist campaign, London's transport has superb security. Yet, that did not stop four suicide bombers July 7 and another similar attempt last Thursday.
One hundred percent passenger screening — an aviation-security model — will not work for trains and buses. It would create staggering manpower requirements and intolerable delays and costs that would destroy public transportation. There also would be little net security benefit. Even if an impenetrable ring of security at train stations were possible, it would merely displace the risk to other places such as shopping malls.
The mere presence of police can deter criminals and all but the most determined suicidal terrorists. Police in train stations may usefully engage passengers and check IDs or bags. Such checks make the environment more hostile to adversaries.
We describe inspections as random. We actually mean something else. Random means without purpose or aim, haphazardly. Surely, that's not our goal. Nor do we mean random in the literal mathematical sense of chosen purely by chance.
What we really mean is selective searching. If police are looking for bombs, they might usefully focus on people with backpacks or large parcels, not women with tiny purses. Random does not mean mindless. It means unpredictable.
Security planners like to build some unpredictability into all security measures. It complicates terrorist planning. Security measures should not become so routine that adversaries by mere observation can identify vulnerabilities and figure out how to exploit them, as terrorists did on 9/11.
We worry that selectivity will turn into racial or ethnic profiling, which would also be bad security. Who says that terrorists will conform to a racial or ethnic stereotype?
The proper basis for selectivity is observed behavior. Customs officials routinely do this. For example, unusual behavior at a border crossing from Canada prompted an alert customs agent in 1999 to ask Ahmed Ressam to open the trunk of his car. He bolted, but was captured. His trunk turned out to be filled with explosives destined for a bombing at Los Angeles International Airport.
Clues about terrorist behavior may come from the demeanor of people as they are being approached, the replies to a few questions or a “How you doin'?”
Some critics charge that all of these increased security measures accomplish little more than reassuring anxious passengers. But this is a legitimate goal too. Terrorists intend their violence to create an atmosphere of fear and alarm that, in turn, will cause people to exaggerate the threat. In combating terrorism, we not only seek to prevent terrorist attacks but also to reduce the terror they create.
Brian Michael Jenkins is a senior adviser to the president of the Rand Corporation and director of the National Transportation Security Center at the Mineta Transportation Institute.
This commentary originally appeared in Newsday on July 26, 2005. Commentary gives RAND researchers a platform to convey insights based on their professional expertise and often on their peer-reviewed research and analysis.