WHEN JOHN F. KENNEDY was elected President of the United States in 1960, Keynesian economic policy entered its American heyday. Keynesianism had been entrenched in the universities for over a decade, and a generation of journalists and civil servants had been instructed in its principles.  There were few critics, and no one paid them any attention. For twenty years it had free rein; the implementation of Keynesian theory, however, culminated in “stagflation.”