Increasing militant activity in western Pakistan poses three key national security threats: an increased potential for major attacks against the United States itself; a growing threat to Pakistani stability; and a hindrance of U.S. efforts to stabilize Afghanistan. This report addresses this issue at length. It also describes the recent upsurge of militant activity on the Pakistani side of the Pakistan-Afghanistan border, as well as the general political climates of Pakistan and Afghanistan and their relationships with the United States.