Roger Cohen reads the tea leaves on Obama's approach to Af-Pak by speaking at length with the British foreign minister:
When I asked if the mission needed substantially more troops, Miliband said, “What I think that you can see from the prime minister’s strategy is that we believe in serious counterinsurgency. Counterinsurgency is a counterterrorist strategy.” [...] That’s a clear rebuttal of the ever-larger school, most often identified with Vice President Joe Biden, advancing the view that Al Qaeda is the real threat, the Taliban much less of one; and so the United States should not commit more military resources to a nation-building struggle in Afghanistan that’s an expensive diversion from core U.S. strategic interests.
Cohen sees an increase of troops in the serious but fewer than 40,000 range. Britain has a reason to give it "one more try":
Three-quarters of all terrorist plots uncovered in Britain in recent years had links to Islamic extremists in Afghanistan or Pakistan.
But is it doable? Or does the attempt to squash it fuel it?