The US has announced that General David McKiernan will be replaced as commander of US and Nato forces in Afghanistan, an unexpected change at a time when thousands of US reinforcements are on their way to deal with a rising Taliban insurgency.
What did McKiernan do wrong?
Mr McKiernan is a highly decorated veteran army commander who led ground forces during the successful initial invasion of Iraq in 2003.
But Defence Secretary Robert Gates and President Barack Obama appear to have concluded that his approach in Afghanistan was too conventional for the complex counter-insurgency environment.
One of the generals who initially served under Mr McKiernan in Iraq is General David Petraeus, now Mr McKiernan's boss and widely credited with using new tactics in Iraq that helped turn around the fortunes of the war.
Those tactics emphasised protecting the population, with units pushed off large bases into smaller outposts to work more closely with local security forces. Policy makers appear to think a new commander would do a better job of bringing similar innovations to Afghanistan.
What experience does the new commander bring?
Lieutenant-General Stanley McChrystal is now the director of the military's joint staff and was long seen as a likely candidate to take up a major battlefield command.
He is most noted for having led the military's Joint Special Operations Command from 2003-08. US policy makers have said that the little-publicised role of the highly secretive JSOC in Iraq was one of the main factors behind the reduction in violence there.
Mr McChrystal's elite forces captured ousted President Saddam Hussein and later tracked down and killed Abu Musab al-Zarqawi, the al Qaeda leader in Iraq who set up and directed suicide bombing networks.
Although JSOC was mainly tasked with hunting down and killing enemies, Mr McChrystal is seen as favouring tactics pioneered by Mr Petraeus to focus on protecting the population.
Mr McChrystal will be joined by a deputy, Lieutenant-General David Rodriguez, who will be day-to-day commander of conventional combat troops, a similar set-up to the command structure in Iraq, letting the overall commander spend more time on strategy.
What do Afghans think of the change?
Under Mr McKiernan, US and Nato forces developed a difficult relationship with the Afghan authorities over the issue of civilian deaths, which have outraged ordinary Afghans and prompted President Hamid Karzai this week to call for a ban on air strikes.
The decision to remove Mr McKiernan was probably taken before reports emerged of an incident last week in western Farah province in which Afghan officials say scores of civilians died.
A spokesman for Mr Karzai described the change as a US administrative matter, but said he hoped the new commander would take more steps to reduce civilian deaths.
A spokesman for the Taliban insurgents said the change was evidence of US "failure" in Afghanistan, more than seven years after the militants' removal from power.