It was much the same story in a recent Marine offensive across Anbar Province, the center of Iraq's insurgency. As part of "River Blitz," Marines took over trouble-spots like Hit, Haditha, Baghdadi, and Ramadi with hardly any shots being fired.

But from the upper ranks to the most junior boots on the ground, few believe the relative ease of this operation means the insurgency in Anbar is over. Instead, the militants are fleeing before the marines arrive, only to return when the marines withdraw. The temporary nature of the Marine takeovers is hampering US efforts to get local cooperation on security.

"They called it River Blitz, but it's been more like operation River Dance,'' says Sgt. Bob Grandfield, from Boston. "This is what insurgents are supposed to do. Run away when we come in. If they fight, they know we'll just kill them."

"They're very perceptive, not stupid at all, and they probably saw tanks were moved here. So they left,'' says Lt. Col Stephen Dinauer from Verona, Wisc, commander of the 3rd Light Armored Reconnaissance Battalion, which headed up operations in Hit. "It's frustrating, because we can't be everywhere at once."

While acknowledging that most top insurgents probably fled prior to the assault, Colonel Dinauer still rates operations in Hit (pronounced Heat) a success. About 40 men were detained, and a number of weapons caches were uncovered. He also believes that insurgents in the area have been "knocked back on their heels," preventing them from planning more attacks and making it easier to move troops around the province.

But while Marines conducted their offensive in Anbar, insurgents struck elsewhere. A suicide car bomb in Hilla, south of Baghdad, killed 125 people - the deadliest single attack since the toppling of Saddam Hussein. Wednesday, unknown gunmen in Baghdad shot and killed a judge involved in the trial of Mr. Hussein.

As the Marines involved in "River Blitz" pull out Anbar Province, a smaller US force is replacing them. One senior marine said he feels "guilty about leaving" Hit because he worries that insurgents will seek reprisals on residents in the absence of local police.

These sentiments echo the scaled-back expectations among troops on the ground. Gone is the talk about breaking the back of the insurgency that was floated before the November battle for Fallujah, where hundreds of militants were dug in and ready to fight.

Instead, the troops speak about a long, painstaking process of intelligence gathering, slowly constricting the corridor along the Euphrates river that has helped foreign militants move into Iraq from Syria and helped domestic militants move men and money.

And they speak about slowly finding a way to train and motivate Iraqi troops to replace the largely failed experiment with the Iraqi National Guard, which has been plagued by desertions, insurgent infiltration, and a refusal to fight because of fears of reprisals against their family members.

Patrolling Hit, a city of 100,000 people, the marines encountered no open hostility. Little boys fascinated by their guns chased after them and young men peppered them with questions in broken English. In five days in the city, one sniper was killed by the marines, and another man was killed after a drive by shooting. In Anbar Province, that's about as quiet as it gets.

But there is also little open or obvious cooperation. Just about an hour before the drive-by shooting, the owner of a house occupied by a team of marines was asked about insurgent activity in the area. "There is no resistance in the entire city of Hit,'' he said. "They left a long time ago."

In a brief meeting with marines to arrange the recovery of two insurgent bodies, a local sheikh told Maj. Derek Horst, "99.9 percent of our people are peaceful people. We don't want problems here."

Such reticence either masks sympathies with the insurgency, or more commonly fear of reprisals. Last October, insurgents moved into the city, reduced the police station to rubble, and beheaded a few locals they deemed too close to US forces. The city's police remain inactive.

Yet as marines left the meeting, another with long experience in the Hit area could hardly detain his disgust. "This guy is one of our biggest problems here. In the past, he's been whipping people up to fight."

In some cities in Anbar, civilians have been killed for simply talking to Marines, and more than a few citizens of Hit on this trip told marine officers that they should either come into the city and stay, or don't come at all, because there are no guarantees of their safety when the troops leave.

The marines say they appreciate civilian fears, but are frustrated that locals don't secure their towns on their own. "It's hard to understand sometimes why people don't stand up for themselves,'' says Sergeant Shawn Hudman of Austin, Texas.