PRO'S: Remember September 11, 2001. Afghanistan under the Taliban provided the al-Qaeda attacks on the Twin Towers and the Pentagon.
Today, the al-Qaeda and its associates have found room for manoeuvre in the tribal areas of Pakistan. For Nato to withdraw from Afghanistan would expose the West to further acts of mass murder.
If the Taliban seized power again, a newly liberal society would once again have to obey their values. Women would have a lower quality of life.
Barack Obama has made Afghanistan a priority and promises a better approach than his predecessor, notably in treating Pakistan as an integral part of the problem.
Improvements in military technology, from communications satellites to pilot-less drones, have made the targeting of an enemy easier.
The increasing size and effectiveness of the Afghan army is encouraging.
CON'S: The continued military mission is costing billions at a time when Western economies are suffering. We simply can't afford to remain fighting in Afghanistan. Pakistan's northern border has become a launching-pad for terrorism.President Hamid Karzai has proved a weak ruler far too tolerant of corruption in his country