Ukraine is a republic under a mixed semi-parliamentary semi-presidential system with separate legislative, executive, and judicial branches. The President is elected by popular vote for a five-year term and is the formal head of state.
Ukraine's legislative branch includes the 450-seat unicameral parliament, the Verkhovna Rada. The parliament is primarily responsible for the formation of the executive branch and the Cabinet of Ministers, which is headed by the Prime Minister. However, the President still retains the authority to nominate the Ministers of the Foreign Affairs and of Defence for parliamentary approval, as well as the power to appoint the Prosecutor General and the head of the Security Service.
Laws, acts of the parliament and the cabinet, presidential decrees, and acts of the Crimean parliament may be abrogated by the Constitutional Court, should they be found to violate the Constitution of Ukraine. Other normative acts are subject to judicial review. The Supreme Court is the main body in the system of courts of general jurisdiction. Local self-government is officially guaranteed. Local councils and city mayors are popularly elected and exercise control over local budgets.
The heads of regional and district administrations are appointed by the President in accordance with the proposals of the Prime-Minister. This system virtually requires an agreement between the President and the Prime-Minister, and has in the past led to problems, such as when President Yushchenko used a legally controversial ways to evade the law by appointing no actual governors or the local leaders, but so called 'temporarily acting' officers, thus evading the need to seek a compromise with the Prime-Minister. This practice was very controversial and required review by the Constitutional Court.
Ukraine has a large number of political parties, many of which have tiny memberships and are unknown to the general public. Small parties often join in multi-party coalitions (electoral blocs) for the purpose of participating in parliamentary elections.