War is as much about propaganda as it is about fighting and weapons. Wars are popular or unpopular, and therefore winnable or unwinnable, depending on their level of public support. The US and NATO should bear this in mind if they want to win the war against the Taliban.
Napoleon promised the people of Europe freedom from oppressive monarchies—he was successful until people no longer believed in him. Bush and Blair used WMDS to scare people into initially supporting the invasion of Iraq.
America lost the war in Vietnam not on the battlefield but on the TV screen as news channels brought the horror of the war into the living room of the American people. During World War I the British concocted the story that the Germans were throwing Belgian babies into the fire. That was to play a major role in influencing American participation in the war.