In communist states, national legislative politics often has a similar structure to the parliaments that exist in liberal republics, with two significant differences. First, the deputies elected to these national legislative bodies are not expected to represent the interests of any particular constituency, but rather the long-term interests of the people as a whole; and second, against Karl Marx's advice, the legislative bodies of communist states are not in permanent session. Rather, they convene once or several times per year in sessions which usually last only a few days. When the national legislative body is not in session, its powers are transferred to a smaller council (often called a presidium) which combines legislative and executive power and in some communist states (such as the Soviet Union before 1990) acts as a collective head of state. In some systems, the presidium is composed of important communist party members who vote the resolutions of the communist party into law.