From the end of World War II to the beginning of 1970s, western capitalist countries generally carried out the policy of state intervention in the economy, and a "golden age" of economic development appeared. The theoretical basis of this policy comes from Keynesianism (economic theory).

First of all, Keynesianism

Also known as "Keynesian economics", it is an economic theory based on Keynes's book "General Theory of Employment, Interest and Money". Advocate the state to adopt expansionary economic policies, advocate state intervention in the economy, and promote economic growth by increasing demand. That is, expanding government expenditure, implementing fiscal deficit, stimulating economy and maintaining prosperity.

Second, the similarities and differences between Keynesianism and Roosevelt's New Deal

After the American Great Crisis broke out, Roosevelt's New Deal coincided with Keynesianism. Both advocate state intervention in the economy. This led to the emergence of a new form of state intervention in the economy. Keynes advocated adopting deficit policy to stimulate economic growth through state investment, which alleviated the disaster caused by the great capitalist crisis in a short time. Keynesianism was adopted by more countries after World War II, and major capitalist countries successively entered the stage of state monopoly capitalism. Roosevelt's New Deal was once regarded by the media as a violation of the requirements of capitalism, a socialist practice, and also related to the success of the Soviet economy at that time. Therefore, in the measures taken by Roosevelt's New Deal, we should try our best to avoid the emergence of state monopoly economy.