The U.S. has canceled three major weapons programs in the past 20 years. The F-22 Raptor was capped at 187 airframes — 194 fewer than the originally planned 381. Then-Secretary of Defense Bob Gates killed the production line in 2009. The M10 Booker light tank was supposed to replace the Bradley Fighting Vehicle. At 42 tons, the Booker proved too heavy for air-deployable use. It was plagued by toxic gas filling the turret after main gun firing. T…