From 1800 to 1921, the whole of Ireland was a part of the United Kingdom of Great Britain and Ireland. However, a Catholic independence movement had demanded for decades that the union between Britain and Ireland be dissolved. The movement was opposed mostly in the northeast, where a large Protestant community was determined to maintain its political ties with Britain.
In 1920, the British Parliament passed an act that divided Ireland into Northern Ireland, consisting of six counties, and Southern Ireland, consisting of 26 counties. Both were to maintain separate parliaments that would remain under the supremacy of the British. This political arrangement proved unworkable, and in 1921, the South was granted home rule by Britain. It became known as the Irish Free State and held dominion status in the British Commonwealth. The North, with a Protestant majority, maintained its traditional ties to Britain. In 1937, the Irish Free State achieved full sovereignty within the Commonwealth, and in 1949 it became a republic. The republic has always been regarded by a majority of its citizens as the legitimate government of the entire island. Since the 1970s, several outlawed paramilitary groups have fought both for and against uniting the island by force. The largest and best-known of these groups has been the Irish Republican Army (IRA), whose continual campaign of bombing and terror to remove the British from the North has contributed significantly to what many people call "the troubles."
Ireland is a parliamentary republic. While the president is the head of state, the prime minister is the head of government. The Oireachstas (Parliament) is divided into two houses, the Dail (House of Representatives) and the Seanad (Senate). The Dail consists of 166 members, elected by citizens over the age of 18 for five years under a system of proportional representation. The Seanad has 60 members. The Dail is the more powerful of the two houses; the Seanad may only consider and amend, but may not veto, bills sent to it by the Dail.
The prime minister is the leader of the party, or coalition of parties, that wins the most seats in the Dail. The major parties are Fianna Fail, which is led by current Prime Minister Bertie Ahern, and Fine Gael. While many observers of Irish politics tend to regard Fine Gael as more moderate on the issue of Irish reunification, in practice there has been little difference between the policies of the two parties. The system of proportional representation, which encourages the formation of smaller parties, makes it difficult for any party to win an outright majority in the Dail. As a result, governments are often short lived and based on coalitions between parties and/or independent legislators.