When the United States recently shot apart a crippled spy satellite over the Pacific Ocean, it also tested an offensive anti-satellite weapon and the potential for ballistic missile defense. “The shot,” as the Pentagon called the $100 million operation conducted on February 20, came immediately after Russia and China put forward a detailed, but flawed, proposal for a treaty to ban space weapons at the United Nations. In response, the United States immediately reaffirmed its unwillingness to participate in any arms control accord covering space.