Current nuclear threats and possible responses

Over the last 50 years, the United States has spent more than \$100 billion developing and building a variety of systems intended to defend its territory against intercontinental-range ballistic missiles. Most of these systems never became operational and ultimately all were judged ineffective. The United States is currently spending about \$10 billion per year developing technologies and systems intended to defend against missiles that might be acquired in the future by North Korea or Iran. This presentation will discuss these efforts ad whether they are likely to be more effective than those of the past. It will also discuss the proper role of anti-ballistic programs at a time when the threat of a nuclear attack on the U.S. by terrorists armed with nuclear weapons is thought to be much higher than the threat of an attack by nuclear-armed ballistic missles.