WASHINGTON — U.S. forces in Iraq have often been accused of being slow to apply hard lessons from Vietnam and elsewhere about how to fight an insurgency. Yet, it seems from the outside, no one has shrugged off the lessons of history more decisively than the insurgents themselves.

The insurgents in Iraq are showing little interest in winning hearts and minds among the majority of Iraqis, in building international legitimacy or in articulating a governing program or even a unified ideology or cause beyond expelling the Americans. They have put forward no single charismatic leader, developed no alternative government or political wing, displayed no intention of amassing territory to govern now.

Rather than employing the classic rebel tactic of provoking the foreign forces to use clumsy and excessive force and kill civilians, they are cutting out the middleman and killing civilians indiscriminately themselves, in addition to more predictable targets like officials of the new government. Bombings have escalated in the past two weeks, and on Thursday a bomb went off in heavy traffic in Baghdad, killing 21 people.

This surge in the killing of civilians reflects how mysterious the long-term strategy remains — and how the rebels' seeming indifference to the past patterns of insurgency is not necessarily good news for anyone.

'Wanton violence'

It is not surprising that reporters, and evidently U.S. intelligence agents, have had great difficulty penetrating this insurgency. What is surprising is that the fighters have made so little effort to advertise unified goals.

Counterinsurgency experts are baffled, wondering if the world is seeing the birth of a new kind of insurgency; if, as in China in the 1930s or Vietnam in the 1940s, it is taking insurgents a few years to organize themselves; or if, as some suspect, there is a simpler explanation.

"Instead of saying, 'What's the logic here, we don't see it,' you could speculate, there is no logic here," said Anthony James Joes, a professor of political science at St. Joseph's University in Philadelphia and the author of several books on the history of guerrilla warfare. The attacks now look like "wanton violence," he continued. "And there's a name for these guys: Losers."

"The insurgents are doing everything wrong now," he said. "Or, anyway, I don't understand why they're doing what they're doing."

Dr. Steven Metz, of the Army War College Strategic Studies Institute, said the insurgency could still be sorting itself out. Yet, he said, "It really is significant that even two years in there hasn't been anything like any kind of political ideology or political spokesman or political wing emerging. It really is a nihilistic insurgency."