A National Missile Defense (NMD) system has been the topic of much debate in the United States for more than half a century. According to its supporters, such a system would provide a sort of protective shield against a limitedmissile attack. In 1999, the U.S. Congress decided that the time for talk was over -- they passed a bill calling for the implementation of the NMD system to defend the United States from a growing number of countries developing long-range missile technologies.

During the 2000 presidential campaign, George W. Bush made it clear that his administration will strongly back a NMD program, even at the expense of damaging U.S.-Russian relations. Russia has protested the U.S. government's plans for a national missile shield. Since taking office, Bush and Secretary of Defense Donald Rumsfeld have pushed ahead with plans to build the $30.2-billion missile-defense system, and might have it operational as soon as 2005.

If you've wondered how the U.S. is planning to target and destroy enemy ballistic missiles, you'll want to read this edition of How Stuff WILL Work. We'll take you inside the U.S. Defense Department's plans, and detail how NMD radar systems and weapon interception will work.