U.S. congressional debate on the 2006 federal budget submitted by President Bush will soon focus on the most expensive defense research and development program in U.S. history -- the ballistic missile defense system.

President Bush wants lawmakers to approve nine billion dollars for the system in the 2006 budget. that is one billion dollars less than he originally wanted.

Missile defense is intended to protect the United States by launching interceptor missiles from land or sea to shoot down incoming missiles fired from overseas. The first eight interceptors have been installed in underground bunkers in Alaska and California.

Washington has spent 92-billion dollars on the futuristic weaponry since the "Star Wars" concept was first introduced by former President Ronald Reagan at the height of the Cold War in 1983.

Opponents point to system failures, rising costs and mixed accuracy test results as reasons to reduce or stop funding.