When the US last went to war, technology was viewed as a critical source of military superiority. Throughout the Gulf war there were frequent reports of Patriot radar-guided missiles intercepting and destroying Iraqi Scuds.
No matter that the Patriot was designed in the late 1970s and built using outdated electronics or that its performance in Kuwait would later come into question - technology, it was widely believed, had won the day.
Today, as the US prepares to launch a "war on terrorism", the role of technology is far less clear. Even as many are questioning whether too much trust has been placed in outdated electronic security systems at airports, others are raising concerns about the use of surveillance technology to root out terrorism. Meanwhile, law enforcement authorities point to the internet as a tool for terrorists.
One of the harsh lessons learned from last week's atrocities is that the security technology used at airports is no match for suicidal zealots intent upon destruction. The ceramic knives and box cutters that the hijackers used to overcome flight crews were apparently undetected by the X-ray systems at US airports. But it seems unlikely that such weapons would have been found by any scanning system designed to detect guns and bombs.
Might technology have provided a better defence? Clearly there are technologies that could be used to increase airport security. More sophisticated baggage scanners are available, at about Dollars 1m (Pounds 600,000) per system.
These create cross-sectional images of bags, rather than viewing the contents from one angle. Yet the cost is high - which is why the use of similar scanners in hospitals is restricted - and it is questionable whether even these systems would have detected a tiny blade if it were secreted in the reinforcing structure of a suitcase.
The alternative approach is to try to identify potentially dangerous passengers. The face-scanning cameras used by some UK stores to spot known shoplifters and by the London borough of Newham to reduce criminal activity might be used to alert authorities to the movement through airports of individuals identified as suspected criminals or terrorists.
Similarly, other forms of biometric identification such as fingerprints, hand geometry, voice recognition or eye scans could - in theory - be used to screen passengers.
However, biometric systems work by matching unique features against records held in a database, which typically limits their use to defined populations such as a company's employees.
One exception may be the extensive databases of fingerprints that already exist in the US. These include immigration records, state driver's licence databases and criminal records.
But integrating these databases and creating systems capable of matching records fast enough to keep lines moving at hundreds of busy airports around the country would be a huge and expensive undertaking.
Moreover, such a system would only be as reliable and up-to-date as the records supplied to it by state and government agencies.
Who would pay for such a system? Would it be replicated internationally? There are no easy answers.
Costs and technicalities aside, the all-important question is whether Americans are ready to accept mass-identification systems for domestic air travel. Until now the public use of biometric identification systems has met strong opposition in the US. When face-scanning cameras were used to identify criminals at the Super Bowl football championship game in Tampa, Florida, earlier this year, there was a public outcry that spawned congressional hearings. Big Brother looms large in these debates.
Those who advocate privacy fear that in the aftermath of last week's terrorist attacks civil liberties may be forfeited to the cause of public safety. On Monday the Electronic Frontier Foundation urged its supporters to write to their members of Congress saying: "I do not believe that sacrificing essential liberties in a vain hope of improving security is good for America or the world. The United States should not take steps toward becoming a police state, or otherwise undermine our own freedom in the name of defending that freedom from terrorist attack, or the terrorists have already won."
Finding a balance between personal freedom and public safety will not be easy in these emotionally charged times. The EFF and other privacy groups are particularly concerned about the call by John Ashcroft, the attorney-general, for Congress to expand the ability of law enforcers to tap telephone lines and monitor e-mail traffic.
What use the terrorists may have made of the internet has yet to be revealed but it is reasonable to assume that they made use of opportunities to send heavily encrypted messages and to gather information easily, quickly and privately via a personal computer.
The terrorist attack is therefore likely to reopen the long-fought battle for free dissemination and export of encryption technology. It is also a serious setback for those who have been lobbying against Carnivore, an internet surveillance system used by the Federal Bureau of Investigation to monitor e-mail within the US, and Echelon, a US surveillance network that allegedly can scan e-mail and wireless communications in many countries for specific content.
Until a week ago, the spooks were in retreat. Now public opinion is beginning to favour intrusions on privacy that would not be felt directly by the vast majority of US internet users. So what if some anonymous federal agent reads my e-mails?
Neither US law enforcement authorities nor privacy groups have yet to propose the obvious compromise - that some civil liberties might be suspended, temporarily, for the duration of this "war against terrorism".
In the meantime, one of the most critical technology systems for air traffic safety is being largely ignored. How could it be that at the turn of a switch hijackers were able to disable transponders and become almost invisible to US air traffic controllers? Had the towers in Boston, New York, Washington, Pennsylvania - or somewhere in between - been able to detect the murderous paths of those four aeroplanes last Tuesday morning, thousands of lives might perhaps have been saved.
louise@ft.com