Social Democracy is a political philosophy that supports intervention by the state in the economy and society to promote social justice. At its heart are Keynesian economics and the welfare state. SD favours a strong state over the market. SD used the power of the state to ensure that markets worked for all. It seeks progress by reform rather than by revolution within liberal democracies.
In 2000, Social Democrats or Socialists were part of government in ten out of the fifteen countries that then made up the European Union. In late 2018, they are in government in two states and in coalition governments in just 7 of the 28 member states.