The directive, she said, “enables us to be flexible, while also exercising restraint in dealing with the threats we face. It continues to be our policy that we shall undertake the least action necessary to mitigate threats.”

One of the central issues is whether such a strike on Syria would be seen as a justified humanitarian intervention, less likely to cause civilian casualties than airstrikes, or whether it would only embolden American adversaries who have themselves been debating how to use the new weapons.

Jason Healey, the director of the Cyber Statecraft Initiative at the Atlantic Council, argues that it is “worth doing to show that cyberoperations are not evil witchcraft but can be humanitarian.”

But others caution whether that would really be the perception.

“Here in the U.S. we tend to view a cyberattack as a de-escalation — it’s less damaging than airstrikes,” said Peter W. Singer, a Brookings Institution scholar and co-author of the recently published book “Cybersecurity and Cyberwar: What Everyone Needs to Know.”

“But elsewhere in the world it may well be viewed as opening up a new realm of warfare,” he said.

There’s little doubt that developing weapons for computer warfare is one of the hottest arenas in defense spending. While the size of the Army and traditional weapons systems are being cut in the Pentagon budget that was released on Monday, cyberweapons and Special Forces are growth areas, though it is difficult to tell precisely how much the government spends.

But Mr. Obama has made no secret of his concerns about using cyberweapons. He narrowed Olympic Games, the program against the Iranian nuclear enrichment program, to make sure that it did not cripple civilian facilities like hospitals.

What he liked about the program was that it was covert and that, if successful, it could help buy time to force the Iranians into negotiations. And that is exactly what happened. But when a technological error in the summer of 2010 resulted in the broadcast of the Stuxnet computer worm around the world, ultimately leading to the revelation of the program’s origins with the N.S.A. and Unit 8200 of Israel, Mr. Obama’s hopes of keeping such programs at arm’s length were dashed.