Marjah, Afghanistan » A month after losing control of their southern base in Marjah, the Taliban have begun to fight back, launching a campaign of assassination and intimidation to frighten people from supporting the U.S. and its Afghan allies.

At least one alleged government sympathizer has been beheaded. There are rumors that others have been killed. Afghans in the town that U.S., Afghan and NATO troops captured in a three-week assault that began Feb. 13 awake to letters posted on their doors warning against helping the troops.

Winning public support in this former Taliban stronghold in Helmand province 360 miles southwest of Kabul is considered essential to preventing insurgents from returning.

The Marjah operation will serve as a model for campaigns elsewhere, including one expected by summer to secure villages around Kandahar, the Taliban's spiritual birthplace and the largest city in the south.

Military commanders believe the Taliban campaign is achieving some success because of questions raised at town meetings: Do the U.S. forces want to shut down the mosques and ban prayer? Will they use lookout posts on their bases to ogle women? Are they going to take farmers' land away?

"Dislocating the insurgents physically was easy. Dislocating them socially -- proving that we're here to stay and to help -- is a lot harder," said Lt. Col. Jeff Rule, the head of operations for Marines in Helmand.

There are no firm figures on how many Taliban are left in Marjah. Marine and Afghan military officials say they believe most of those still here are from the area and the foreign fighters have fled.

Regardless of Taliban numbers, their influence is still felt.

New cell phone towers brought phone service to Marjah a little over a week ago. But the service doesn't work at night because the Taliban threaten or bribe tower operators to shut off the network, presumably to prevent people from alerting troops and police as they plant bombs after dark.

Some of the workers on canal-clearing projects have been threatened or have been beaten up by insurgents.

At least one canal worker who received threats returned and said he will keep working despite the risk, said Maj. David Fennell, who oversees about 15 civil affairs troops working to win over the population.

"That's when you know that you fought the Taliban and you won," Fennell said. "I tell my team time and time again: 'What did we just do today? We hit the Taliban in the mouth.' "

"My sense is that the Taliban will re-infiltrate in due course as the Afghan government fails to live up to the modest expectations NATO has of it," says Mervyn Patterson, a former U.N. political affairs expert in Afghanistan. "I do not think that the Taliban have been weakened in Helmand by the loss of Marjah. They have been having ups and downs, and this was a modest down, but not something that is significant."