The only military command focused solely on defending U.S. soil was declared fully operational Thursday, two years after the terrorist attack that led to its formation. Enlarged news photographs from Sept. 11, 2001, hang on the walls at U.S. Northern Command headquarters - reminders to people like Army Lt. Col. Shelly Stellwagen. "Having lost eight friends at the Pentagon, this is a grudge match, and we're going to win," she said. Over the past year, officials at this Air Force base near Colorado Springs have been tweaking Northcom's structure and operations in tackling its twin missions of defending the country...