WASHINGTON, Nov 16 - Russia's X-31 anti-ship missile is a devastating weapon. Capable of traveling at 2,000 mph, the 15-foot missile skims over the ocean until it slams into its target and explodes. It also can be modified to seek out and destroy radar systems, such as those used to guide the U.S. military's Patriot missiles, defense analysts say. For years, the U.S. military has sought to develop an effective defense against the X-31. In 1999, Boeing Co. announced in St. Louis that it had won an $18.8 million contract from the Navy to acquire 34 of the Russian missiles...