Political Realities and Afghanistan

This is the best explanation I've seen as to why Obama cannot easily disengage from Afghanistan, by Dan Froomkin on Huffington Post:

"He has figured out that the stakes are not as great as he once believed;
that the commitment looks open-ended; that the conditions there are not
promising; and that if he's not careful, this will be a dead weight around the
rest of his presidency," says Harvard international relations professor Stephen
M. Walt, who also blogs for Foreign Policy. "And so he's looking for an
alternative."

It took Obama this long to figure it out, Walt told me, because "I don't
think this was an issue he had mastered before he became president. I think that
early in the administration, most of the advice he was getting was from one
side. It was mostly coming from people who were sort of invested in the
mission."

Since then, Walt says, Obama has heard a lot more from others in the
administration -- including Biden -- who are skeptical of a military solution in
Afghanistan. The Afghan election was a "sobering moment" that made it clear
"just how weak our Afghan partner was," Walt says. The U.S. ambassador in Kabul
also recently informed the White House of his deep concerns about sending more
U.S. troops to Afghanistan until Karzai's government gets it together. And for
good measure, White House Budget Director Peter Orszag last week acknowledged
that sending 40,000 more U.S. troops to Afghanistan would cost an extra $40
billion a year.

"If political realities were not a constraint, disengagement from
Afghanistan would be the best course of action," Pillar says. "But I accept the
political reality that that is off the table. The president would get pilloried
as being a softie and as not having the courage and determination supposedly to
stand up for U.S. security. I don't buy any of that criticism myself, but that
would be the political reality he's facing."