Under the constitution of 1937, as amended, legislative power is vested in the Oireachtas (national parliament), which consists of the president and two houses—Dáil Éireann (house of representatives) and Seanad Éireann (senate)—and sits in Dublin, the capital city. The president is elected by popular vote for seven years. Members of the Dáil, who are also elected by popular suffrage, using the single transferable vote, represent constituencies determined by law and serve five-year terms. These constituencies, none of which may return fewer than three members, must be revised at least once every 12 years, and the ratio between the number of members to be elected for each constituency and its population as ascertained at the last census must be the same, as far as practicable, throughout the country. Since 1981, there have been 166 seats in the Dáil.
The Seanad consists of 60 members: 49 elected from five panels of candidates representing (a) industry and commerce, (b) agricultural and allied interests and fisheries, (c) labor, (d) cultural and educational interests, and (e) public administration and social services; 6 elected by the universities; and 11 nominated by the taoiseach (prime minister). Elections for the Seanad must be held within 90 days of the dissolution of the Dáil; the electorate consists of members of the outgoing Seanad, members of the incoming Dáil, members of county councils, and county borough authorities. The taoiseach is assisted by a tánaiste (deputy prime minister) and at least six but not more than 14 other ministers. The constitution provides for popular referendums on certain bills of national importance passed by the Oireachtas. Suffrage is universal at age 18.