The World Trade Center was still a smoking ruin when America was seized by a new horror. Within a week of the USA's worst terrorist attack, seven letters powdered with finely milled Anthrax spores were mailed to persons in the government and press agencies -- sickening dozens and killing five -- including the hapless mail handlers who contacted unopened envelopes. Countless other "copycat" attacks were mailed using harmless substances such as artificial creamer, shutting down government offices and sending thousands to hospitals to be "tested" -- although they were offered little more than reassurance and perscriptions for antibiotics that would quickly become scarce. Government agencies fanned the flames with suggestions that Americans seal their doors and windows with duct tape to avoid contamination. Inhalation of even a few spores could lead to a fatal pneumonia -- raising fantastic scenarios of abandoned urban centers, empty subways, and mass casualties in a country already reeling from the destruction of the core of its greatest city.

More than a decade later, the DNA of the anthrax strain is known to have originated from a US biological warfare laboratory, apparently the result of a "Lone Wolf" attack unrelated to the World Trade Center catastrophe -- although the investigation, dogged by missteps and false statements, never fully implicated any individual. Over a billion dollars was spent in cleanup.

Easy to isolate, culture and distribute, Anthrax still remains a terrorist weapon of choice that lies within the reach of a single individual with a rudimentary laboratory, and such attacks are likely to be repeated in the future. For that matter, it is still possible to catch Anthrax bacterial infections from natural sources, such as improperly cured sheep skins. Fortunately, exposure is easily treated with antibiotics, although such supplies might be quickly exhausted in a major attack.

As we place our trust in flimsy federal safeguards against future attacks, the Anthrax letters of 2001 teach a lesson worth remembering -- terror begets terror, and in the froth of panic it is wise to watch your back. Your worst enemy might be your own twisted government.