AP Photo

It's time to get real about Afghanistan. Withdrawal is not a serious option. The United States, NATO, the European Union, and other nations have invested massively in stabilizing the country over the past eight years, and they will not"”and should not"”abandon it because the Taliban is proving a tougher foe than anticipated. But it's also time for the Obama administration to get real about the country. There continues to be a large gap between the goals being outlined by the administration and the means available to achieve them. This gap is best closed not by sending in tens of thousands more troops but rather by understanding the limits of what we can reasonably achieve in Afghanistan.

The most important reality of the post-9/11 world has been the lack of any major...