A planned assault on a major Taliban stronghold in southern Afghanistan is the first real test of a new US-led counter-insurgency strategy to re-establish government control and end the war.
Operation Mushtarak is an experiment in combining the military objective of eradicating the Taliban with the need to replace their brand of harsh control with the civilian authority of Kabul, analysts said.
The battle for Marjah, an agricultural plain in the central Helmand River valley, is the proving ground for US General Stanley McChrystal's counter-insurgency theory for winning the hearts and minds of Afghan people.
Married to President Hamid Karzai's programme of encouraging Taliban to quit the fight and return to mainstream society -- and US President Barack Obama's troop surge -- McChrystal's plan is being played out in the poppy fields of Helmand.
"This fight is aimed at showing the Taliban and other anti-government groups the power of the government, to show them there is no place they can relax so they will eventually want to reconcile," said political analyst Ahmad Saedi.
Thousands of US, NATO and Afghan troops have massed around Marjah preparing for a fight that military commanders say will eradicate the Taliban from one of the last places under their sway in Helmand province.
The Taliban too are massing fighters, with their purported spokesmen predicting a fierce battle.
Waheed Mujda, a political analyst and author who served in the Taliban's foreign ministry during its 1996-2001 rule, said the insurgents are unlikely to break cover for hand-to-hand combat.
They are expected to mine the area, home to 80,000 mostly farming people, with improvised explosive devices (IEDs) which, along with suicide attacks, have become a staple Taliban weapon as their tactics morph into guerilla warfare.
"The Taliban want to fight but they will not do so directly because they know that would mean high casualties," said Mujda.
"Instead they will bother foreign forces by fighting and fleeing, and the foreigners will also take casualties from the IEDs," he said.
Operation Mushtarak -- meaning "together" -- is expected to begin within days, with thousands of US Marines and NATO troops, along with Afghan security forces massed around Marjah town, about 20 kilometres (12 miles) south of the provincial capital Lashkar Gah.
The region is one of the world's biggest opium poppy growing regions, where insurgents are exploiting an irrigation system built in the 1950s with US aid aimed at turning the region into Afghanistan's bread basket.
Residents who are leaving the area say the Taliban maintain control through fear and violence.
Western military commanders, including McChrystal who heads the 113,000 US and NATO forces in Afghanistan set to rise to around 150,000 by August, are prepared for high casualties in the battle for Marjah.
They are also prepared for the need to stay until political and civil control has been established, paving the way for development.
Norine MacDonald, president of London-based think tank the International Council on Security and Development, said it is important that troops stay to consolidate their victory with civilian control.
"Then for those who want to bring the Taliban to the negotiating table we have some military leverage," she said, referring to efforts to talk peace with the Taliban leadership.
"The military effort and the 'negotiating' effort have to be coordinated," she said.
Military officials said Mushtarak was planned in close cooperation with the Afghan government and that lessons of past failures had been learned.
The war against the Taliban is now into a ninth year and Obama wants to start bringing American troops home in mid 2011.
"If you push the insurgents off but you don't stay in place then the strategy is worth nothing," said the spokesman for NATO's International Security Assistance Force (ISAF), Brigadier General Eric Tremblay.
"The operation has to create an environment in which governance and development can be established.
"It's not supposed to be a show of strength militarily. We have said all along it's not necessarily about killing them (the insurgents) but if they are fighting ISAF and Afghan forces they will be killed.