The island is divided between the Republic of Ireland, an independent state, and Northern Ireland (a constituent country of the United Kingdom). They share an open border and both are part of the Common Travel Area.
The Republic of Ireland is a member of the European Union while the United Kingdom is a former member, having both acceded to its precursor entity, the European Economic Community [EEC], in 1973, and as a consequence there is free movement of people, goods, services and capital across the border.
The Republic of Ireland is a parliamentary democracy based on the British model, with a written constitution and a popularly elected president who has mostly ceremonial powers. The government is headed by a prime minister, the Taoiseach, who is appointed by the President on the nomination of the lower house of parliament, the Dáil. Members of the government are chosen from both the Dáil and the upper house of parliament, the Seanad. Its capital is Dublin.
The republic today ranks amongst the wealthiest countries in the world in terms of GDP per capita and in 2015 was ranked the sixth most developed nation in the world by the United Nations' Human Development Index. A period of rapid economic expansion from 1995 onwards became known as the Celtic Tiger period, was brought to an end in 2008 with an unprecedented financial crisis and an economic depression in 2009.
Northern Ireland is a part of the United Kingdom with a local executive and assembly which exercise devolved powers. The executive is jointly headed by the first and deputy first minister, with the ministries being allocated in proportion with each party's representation in the assembly. Its capital is Belfast.
Ultimately political power is held by the UK government, from which Northern Ireland has gone through intermittent periods of direct rule during which devolved powers have been suspended. Northern Ireland elects 18 of the UK House of Commons' 650 MPs. The Northern Ireland Secretary is a cabinet-level post in the British government.
Along with England and Wales and with Scotland, Northern Ireland forms one of the three separate legal jurisdictions of the UK, all of which share the Supreme Court of the United Kingdom as their court of final appeal.
As part of the Good Friday Agreement, the British and Irish governments agreed on the creation of all-island institutions and areas of cooperation. The North/South Ministerial Council is an institution through which ministers from the Government of Ireland and the Northern Ireland Executive agree all-island policies. At least six of these policy areas must have an associated all-island "implementation bodies," and at least six others must be implemented separately in each jurisdiction. The implementation bodies are: Waterways Ireland, the Food Safety Promotion Board, InterTradeIreland, the Special European Union Programmes Body, the North/South Language Body and the Foyle, Carlingford and Irish Lights Commission.
The British–Irish Intergovernmental Conference provides for co-operation between the Government of Ireland and the Government of the United Kingdom on all matters of mutual interest, especially Northern Ireland. In light of the Republic's particular interest in the governance of Northern Ireland, "regular and frequent" meetings co-chaired by the ROI Minister for Foreign Affairs and the UK Secretary of State for Northern Ireland, dealing with non-devolved matters to do with Northern Ireland and non-devolved all-Ireland issues, are required to take place under the establishing treaty.
The North/South Inter-Parliamentary Association is a joint parliamentary forum for the island of Ireland. It has no formal powers but operates as a forum for discussing matters of common concern between the respective legislatures.