LAST month President Obama announced plans for withdrawing by next summer the approximately 30,000 American troops sent to Afghanistan as part of the 2009 surge.

We commend the president for sticking to the July date he had outlined for beginning the withdrawal. However, his plan would not remove all regular combat troops until 2014. We believe the United States is capable of achieving this goal by the end of 2012. America would be more secure and stronger economically if we recognized that we have largely achieved our objectives in Afghanistan and moved aggressively to bring our troops and tax dollars home.

After Al Qaeda attacked the United States on Sept. 11, 2001, we rightly sought to bring to justice those who attacked us, to eliminate Al Qaeda’s safe havens and training camps in Afghanistan, and to remove the terrorist-allied Taliban government. With hard work and sacrifice, our troops, intelligence personnel and diplomatic corps have skillfully achieved these objectives, culminating in the death of Osama bin Laden.

But over the past 10 years, our mission expanded to include a fourth goal: nation-building. That is what we are bogged down in now: a prolonged effort to create a strong central government, a national police force and an army, and civic institutions in a nation that never had any to begin with. Let’s not forget that Afghanistan has been a tribal society for millenniums.