Require National Vote 65% in favor of Declaration of War

Over the past 50 years presidents have lend our country into wars that we don't want. Congress seems to have abdicated its responsibility to the President. This seems to allow even more concentration power. War is expensive and the public really needs more of a say in such an important decision. Obviously if we are attacked directly then a state of war exists automatically, though we would need to define "who" who did the attacking clearly enough.