4,415 U.S. troops, including U.S. Army Specialist Casey Sheehan, never came home from Iraq. At least not alive. Tens of thousands more have had their lives forever shattered due to permanent physical and emotional injury. Hundreds of thousands of innocent Iraqis were also slaughtered and maimed in the bargain.

And tonight, after all of that time, we're still left wondering: What was that "noble cause"?