Afghanistan is a tragedy. But it has been a tragedy for centuries. After more than a decade of attempted nation-building, the U.S. should accelerate its withdrawal. Only the Afghans can make their future.

Washington intervened in Afghanistan for a specific purpose: destroy al Qaeda and oust the Taliban for hosting anti-American terrorists. The U.S. quickly fulfilled both objectives.

The best hope for the U.S. to create a stable and peaceful Afghanistan was in 2002 and 2003. But the Bush administration was fixated on Iraq and quickly withdrew military resources from Afghanistan, promoting failure there. The Obama administration twice increased troop levels in Afghanistan in a desperate attempt to recoup lost ground.

Since then, the U.S. military has put the Taliban on the defensive and allied commanders publicly profess support for the administration’s planned withdrawal in 2014. However, on a recent trip to Afghanistan I found less confidence in private. So long as the Afghan government remains corrupt and incompetent and the Taliban finds aid and sanctuary in neighboring Pakistan, the vision of a stable, peaceful Afghanistan likely will remain a chimera.

There is another, deeper problem with western attempts at nation-building in Central Asia. Afghanistan is not America or Europe, a fact highlighted by the recent deadly riots in response to the Koran burning by U.S. troops. Politicians, some allied with President Hamid Karzai, even encouraged the violence. Last year a similar mob slaughtered United Nations staffers after a Koran burning in America.

Afghanistan may eventually end up with a reasonably liberal society and effective government, but only on its own accord. There are, in fact, many Afghans, particularly women, who desire liberty and equality. However, the U.S. cannot turn Afghanistan into a modern nation-state, at least at reasonable cost in reasonable time.

It is time for the Obama administration to recognize this and stop sacrificing American lives.

Washington should accelerate its troop withdrawal. Along the way there is much the U.S. should do: offer sanctuary to liberal-minded Afghans, press negotiations with the Taliban setting America’s red lines (such as al Qaeda’s return), and engage regional powers, including Iran, to limit the spread of conflict.

Equally important, the U.S. should learn from its failure. No more attempts at global social engineering.

There are no good options in Afghanistan. But after a decade of war in Central Asia it is time for America to leave.