Now that the Nov. 7 runoff election in Afghanistan has been canceled and Hamid Karzai announced the official winner of the Aug. 20 vote, President Obama must end the uncertainty surrounding the future of U.S. engagement in the region, and announce a strategy for moving forward in Afghanistan.

The flawed Afghan election was a setback to international efforts to stabilize Afghanistan. However, the stakes for the U.S. and international community in preventing the country from again serving as a base for global terrorists are too high to consider scaling back the mission there.

Western nations often focus on the Taliban's resurgence in the south since 2006 as evidence that the situation in Afghanistan is hopeless and the war unwinnable. But many Afghans take a different view. Women and girls (including several female parliamentarians I met on a trip to Afghanistan in June) tout their return to school and active participation in society as proof that life is better for average Afghans than it was under Taliban rule from 1996 to 2001. Several public polls also show that most Afghans want coalition troops in their country to protect them against the Taliban so long as those troops take steps to limit the number of civilian casualties.

While the Obama administration is right to demand cleaner rule from Karzai, it also must be realistic about the security situation.

In the early years of Karzai's first administration, he was viewed as a capable consensus builder, enjoying wide respect from the international community. Only in the past few years has opinion -- domestic and foreign -- turned against him. Interestingly, the dip in public support for Karzai coincides with the resurgence of the Taliban and the deteriorating security situation. Karzai's unwillingness to rein in rampant corruption within his own government also has soured his image.

Karzai must distance himself from warlords, who have committed human rights atrocities, and narco-traffickers who indirectly benefit the Taliban. For starters, he must establish a Cabinet of competent technocrats who can work effectively with the U.S. and NATO partners in bringing development and reconstruction to the Afghan people.

Part of the reason Karzai's reputation has suffered is the deteriorating security situation -- so it stands to reason that providing additional U.S. troops to reverse Taliban momentum, as Gen. Stanley McChrystal has requested, would also increase the credibility of the Afghan regime. While the Obama administration is right to demand cleaner rule from Karzai, it also must be realistic about the security situation and acknowledge that stemming Taliban advances is vital to U.S. national security interests.

A return to Taliban rule would embolden a generation of international terrorists, provide space and latitude for al-Qaida to press its global terrorist agenda, and allow the Taliban to project its extremist influence back intoPakistan, a nuclear-armed nation already practically at civil war with extremists based in its own territory. The U.S. must find ways to work with President Karzai to keep the Taliban and its terrorist affiliates at bay.

Lisa Curtis is a senior research fellow in the Asian Studies Center at The Heritage Foundation.