The Keynesian School of Economics
The Keynesian School of economics was proposed in the 20th century by Keynes. This form of economics involves some government control over the economy in the form of subsidies, regulations, and governmental spending. The idea of Keynesian economics ... is, particularly during a downturn of the economy, the government should spend money to boost aggregate demand, and creating more jobs to help the economy. It does this by using high taxes to subsidize companies within the private sector, and then to spend its own money on public sector jobs. The government then also uses different forms of regulation to help the keep customers safe, and to help the economy grow.
Keynesian economics is often confused with the idea of full governmental control over the economy, otherwise known as Socialism or Communism. The key difference between Keynesian Economics and Socialism/Communism is that instead of taking full control over the private sector, as is done in Socialism and Communism, the government spends money and creates legislation to regulate the private sector. While governmental influence still plays a part in the economy, privately owned businesses still exist and play an enormous role in shaping the economy.
This form of economics is supported primarily by liberals, and in particular the Democratic party of the United States of America