In one more Afghanistan tragedy, Staff Sergeant Robert Bales is accused of the heinous crime of murdering 17 Afghan civilians. The event provides an opportunity for the U.S. to accelerate its troop withdrawal and save innumerable lives over the next several years. It offers a moment to pause and reexamine what our continuing national purpose is in this longest war in U.S. history.

The original mission in Afghanistan as explained to the American people on October 7, 2001 by George W. Bush was to bring al Qaeda in Afghanistan to justice, destroy their training bases there, and punish the Taliban regime for harboring them. After the 9/11 attacks, such intervention was certainly called for and well executed. But that mission should have ended years ago. The Taliban regime was quickly toppled, al Qaeda driven from their training camps, and less than a few hundred have been in the country for some time. More recently, Osama Bin Laden has been killed and the number of al Qaeda has been estimated at under a hundred.

Yet somehow, this war has evolved into the U.S. propping up a corrupt central government that lacks the power to impose its rule much beyond Kabul. In one of the poorest countries in the world and a land where regional tribal chiefs have real local power, we have spent hundreds of billions of dollars supporting Hamid Karzai and trying to lift the economic fortunes of Afghans. This challenge of economic and lifestyle uplift is tough enough in our own cities much less in places with names like Kandahar and Jalalabad. With a people that have been historically outstanding fighters, defeating the mighty British army and next door Soviet Union, we have been trying to "train" an Afghan fighting force for the last 8 years. Increasingly the Afghans are turning their guns on American and allied trainers. At a time when drug use is one of our nation's greatest domestic problems, we defend a country that is the world's largest poppy grower for heroin. At a time when reducing our budget deficit rocks our nation's politics, we spend billions a month on this faraway endeavor. The Taliban, as ruthless as they are, have never said their goal is to attack the U.S. mainland. Our foreign presence in many ways builds resentment among many Afghans, and neighboring Pakistanis where public approval of the U.S. continues below 15 percent.

The latest New York Times/CBS News poll completed March 25th found that 69 percent of Americans feel we should not be in the Afghanistan war. This follows a Pew Research Center poll in which 57 percent of Americans indicated the U.S. should speed up the Afghanistan withdrawal.

Enough is enough. We have lost thousands of American lives, suffered tens of thousands of American casualties, and spent hundreds of billions of American dollars on this war effort. Our original mission has been fulfilled. A dramatically smaller counterterrorism ability may make sense for a few more years. But lets bring our brave troops home as soon as we can. Every extra month we are there results in more U.S. death, injury and expense. Nothing further will be accomplished whether we stay until the end of 2014 versus the end of 2012. This should be a decision made by our civilian leadership and Commander in Chief who assess our country's national interest taking into account overall domestic needs and global requirements, not Commanders in the field who, though honorable and talented, have a different perspective.

Sergeant Bales reported killing of innocent Afghan civilians gives us an opportunity to reflect on this long war and say at last, bring our troops home!