Mid-term elections take place every four years, to elect members of Congress. Voters elect the entire House of Representatives, a third of the Senate and many state and local officials. The elections fall in the middle of a president's four-year term. In 2010, mid-term elections fall on 2 November.

National convention The party assembly held every four years at which state delegates from across the country gather to vote on the party's candidate for president and vice-president.

National conventions serve mainly to formalise the will of the majority of voters, expressed during the earlier state primaries and caucuses. Usually the winner of the greatest number of delegates from the primary and caucus states will receive the party's nomination.

Today the event is largely a platform for the prospective candidate to present their choice of vice-presidential running mate and to draw up their policy agenda.