 The US military could not make effective use of the single radar installation based in Hawaii (it was used part-time as a training device) and visual spotters in the Philippines that should have provided an early warning to their fighter squadrons.In later stages, US bombers effectively destroyed many Japanese cities with conventional or incendiary bombs before the use of atomic bombs on Hiroshima and Nagasaki.After World War II, the major powers built heavy strategic bombers to carry nuclear weapons.