Under the cover of strict secrecy, the United States is thought to be training a potent new offensive force a squad of military and intelligence computer hackers who can bring America's enemies to their knees without a shot being fired in anger.
Almost all government statements about possible future cyberwars have focused on the need for strong defensive measures against attacks from hostile governments or "cyber-terrorists".
Last month President Bill Clinton ordered that security be increased for national computer systems in the military, intelligence, governmental and banking sectors.
In contrast, little has been said about the means Washington is developing to launch cyber-measures against its enemies. No equivalent presidential directive is under consideration.
But it is inconceivable that the Pentagon and the CIA would neglect such a powerful weapon, and a trail of evidence suggests their plans are well advanced.
At a Senate hearing last month a Democratic senator, Carl Levin, asked the CIA director, George Tenet, whether the government was developing an offensive hacking capacity. Mr Tenet said the country "can rest assured that we're not asleep at the switch in this regard".
The Pentagon is understood to have carried out an internal restructuring to give greater urgency to offensive computer operations, and to have ordered military commanders to review their war plans with cyberweapons in mind. An unnamed congressional source told the Washington Post this week that "some pretty aggressive thinking" was going on.
The extent of such capabilities is one of Washington's most closely guarded secrets, but sources say the government has explored ways of planting computer viruses or "logic bombs" in foreign networks to render them useless in wartime.
Among the options said to have been considered are shutting down computerised enemy air defence networks, shutting off power and telephone networks in major cities, feeding false data about troop and weapons deployment into enemy military information networks, and "morphing" television propaganda into foreign broadcasts.
The attractions of such capabilities are obvious, not least to a public that has been led to believe in "smart wars" which achieve their objectives without the loss of American lives.
But the policy "is at a fairly immature stage of development", according to the Washington Post's congressional source, and the Pentagon is unwilling to discuss it.
The gulf between what the technology is capable of and what it can deliver, especially in wartime, helps to explain the hesitancy. Large-scale computer attacks require enormous amounts of comprehensive information about rival systems, which are not easy to obtain or update.
"We like to think of electronic attack as the ultimate in precision weapons," said Vice-Admiral Arthur Cebrowski, a navy authority on such systems. "But these are not necessarily very precise instruments."
One of the many unknowns is the effect that feeding false information into one part of an enemy's computer system is likely to have elsewhere.
There is also debate about the command structure for cyber-operations.
The intelligence oversight committees in the US Congress have pressed for greater clarity and for co-ordination between the Pentagon, the CIA and the FBI.
They want to ensure that any government-sponsored hackers do not interfere with rival agencies' operations and that they obey similar rules.
