Mikheil Gorbachev, the last head of state to organize the withdrawal of a failed occupation from Afghanistan, has some advice for President Barack Obama: get out while the getting’s good.

Soviet troops flee Afghanistan in the late 1980s“There is no prospect of a military solution,” Gorbachev warned, “what we need is the reconciliation of Afghan society – and they should be preparing the ground for withdrawal rather than additional troops.”
Gorbachev Advises Obama to Withdraw From Afghanistan -- News from Antiwar.com

Unfortunately, I don't think the Yanks have any intention of leaving...