New York Times:

LONDON — The top military commander in Afghanistan, Gen. Stanley A. McChrystal, rejected calls for scaling down military objectives there on Thursday and said Washington did not have unlimited time to settle on a new strategy to pursue the eight-year-old war.
In a speech to the International Institute for Strategic Studies, a private policy group here, General McChrystal said that the situation in Afghanistan was serious and that “neither success nor failure can be taken for granted.”
He was speaking in Britain — America’s close ally in Afghanistan — a day after he had participated by video link from London in a White House strategy session on the war that included President Obama, Vice President Joseph R. Biden Jr. and an array of senior advisers.
General McChrystal was asked by a member of an audience that included retired military commanders and security specialists whether he would support an idea put forward by Mr. Biden to scale back the American military presence in Afghanistan to focus on tracking down the leaders of Al Qaeda, in place of the current broader effort now under way to defeat the Taliban.
“The short answer is: no,” he said. “You have to navigate from where you are, not where you wish to be. A strategy that does not leave Afghanistan in a stable position is probably a short-sighted strategy.”
He did not mention Mr. Biden by name.

The rest here.