An advisory panel to Defense Secretary Donald Rumsfeld is evaluating the long-term viability of the U.S. nuclear stockpile in an assessment that could lay the groundwork for a new class of nuclear weapons. The Defense Science Board earlier this month established the Task Force on Nuclear Capabilities to examine options for keeping keeping strategic forces well-equipped with an inventory of weapons that were designed 20 years ago to last as long as 30 more years. John Foster, a former Los...