SPACE WEAPONS:
Although it is difficult to compile actual spending totals across the complete spectrum of space-based defense programs (including classified "off-budget" "black projects"), the U.S. has certainly invested well over $100 billion on "SDI" and follow-on programs, and holds a commanding lead over all current or potential future adversaries in the realm of space technology/warfare.
http://en.wikipedia.org/wiki/Strateg...nse_Initiative