(Editor's Note: This story has been updated to include comments from defense budget analysts.) The Congressional Budget Office is reporting that, if current laws remain unchanged, the federal debt is on track to exceed 100 percent of all U.S. economic output by 2040, thereby constraining defense spending and compromising national security. The federal debt "is now equivalent to about 74 percent of all U.S. annual output, or gross domestic product -- a higher percentage than at any point in...