Hunkered down in the White House this week, top US officials thrashed out options for Afghanistan in a dispute that has split the administration and could decide the future of the fight against al-Qaeda and President Barack Obama’s hopes of a second term.

The likely outcome of that debate – which has pitted General Stanley McCrystal, the administration’s handpicked commander in Afghanistan, against war sceptics in Congress and at the highest levels of government – is coming into view.