As we move forward, some people will ask why we need a firm time line. The answer is clear: our goal is not to build a country in America's image, or to eradicate every vestige of the Taliban. These objectives would require many more years, many more dollars, and many more American lives. Our goal is to destroy al Qaeda, and we are on a path to do exactly that. Afghans want to fully assert their sovereignty and build a lasting peace. That requires a clear time line to wind down the war. Others will ask why we don't leave immediately. That answer is also clear: we must give Afghanistan the opportunity to stabilize. Otherwise, our gains could be lost, and al Qaeda could establish itself once more. And as commander in chief, I refuse to let that happen. I recognize that many Americans are tired of war. As president, nothing is more wrenching than signing a letter to a family of the fallen, or looking in the eyes of a child who will grow up without a mother or father. I will not keep Americans in harm's way a single day longer than is absolutely required for our national security. But we must finish the job we started in Afghanistan and end this war responsibly. My fellow Americans, we have traveled through more than a decade under the dark cloud of war. Yet here, in the pre-dawn darkness of Afghanistan, we can see the light of a new day