Why doesn't this surprise me?
President Obama wants to be re-elected, so he is throwing Afghanistan under the bus in order to make himself look good.
Of course, that follows a long, long pattern of US betrayal of allies when it was politically opportune to do so. Always, always during a Democratic presidency.
It is a sad fact: the President of the United States is a political hack, without direction or vision beyond what his financiers have been telling him to do, and even that has been spotty. For them, of course, he's the only game in town. He knows that, and is, I think, honestly perplexed that his honorable opposition isn't willing to get on the deal.
Look at the historical record: Democratic presidents, almost without fail, get the US into trouble internationally with poor decisions, bellicosity and incompetence. Kennedy started US involvement in Vietnam and Johnson escalated, and a Democratic congress cut Vietnam off in their final hour of need. Carter had the Desert One fiasco, while Clinton had the Balkans and alienated Russia for at least a generation. Obama may have inherited both Iraq and Afghanistan, but is doing just fine screwing things up in Libya and Sudan.
I think the problem with the Democrats and foreign policy is that they both don't really care about it (domestic politics is where the money is and where careers are made) and when they do, behave like Wilsonists and present carefully thought out, brilliant and complete unworkable solutions that make everyone shake their heads and go "what are they smoking?" whilst, of course, at the same time solving nothing. Carter's sole claim to fame is the Egypt-Israeli peace deal, and that got Sadat murdered, Clinton failed to achieve anything in the Middle East.
The true colors of the Democrats is that they cannot be trusted with foreign policy because they consistently screw things up. The days of Sam Nunn and the Senate Democratic Hawks are long, long gone, and there is no one of his character left. His retirement from the Senate was because the party shifted left: he could no longer be a part of that.
You can't run a super-power based on the politics you need to put together a coalition of gays, minorities and unions. You won't care about the hard military and defense decisions you have to make if all you are worried about is playing gay marriage advocates against Black church goers in order to keep the support of both. You won't be able to call upon everyone to make sacrifices when you think a sacrifice is 8% growth of the money for your union supporters, rather than 15%.
The Democrats are thoroughly corrupt and corrupted, unable to see, given the degree of support given a slimeball like Wieners, that what they are willing to accept as the new normal is far, far beyond the pale of normality.
You can't run a super-power based on wishful thinking and plans to have everyone sign kumbya around a camp fire making smores.