2009 Lisbon II referendum

The Twenty-eighth Amendment of the Constitution of Ireland permitted the state to ratify the Lisbon Treaty of the European Union. It was effected by the Twenty-eighth Amendment of the Constitution (Treaty of Lisbon) Act 2009, which was approved by referendum on 2 October 2009 sometimes known as the Lisbon II referendum. The amendment was approved by the Irish electorate by 67.1% to 32.9%, on a turnout of 59%. Following the referendum, Dáil Éireann (the lower house of parliament) gave its approval to the Treaty on 8 October 2009. The President of Ireland Mary McAleese signed the amendment of the constitution into law on 15 October. The Treaty of Lisbon entered into force on 1 December 2009.