Non-revolutionary socialists were inspired by the writings of John Stuart Mill, and later John Maynard Keynes and the Keynesians, who provided theoretical justification for state involvement in existing market economies.[citation needed] According to the Keynesians, if business cycles could be smoothed out by national ownership of key industries and state direction of their investment, class antagonism would be effectively tamed.[citation needed]They argue that a compact would form between labour and the capitalist class and that there would be no need for revolution. Joan Robinson and Michael Kalecki formed the basis of a critical post-Keynesian economics that at times went well beyond liberal reformism[clarification needed].