Twenty-sixth Amendment of the Constitution of Ireland

The Twenty-sixth Amendment of the Constitution of Ireland permitted the state to ratify the Treaty of Nice. It was effected by the Twenty-sixth Amendment of the Constitution Act, 2002, which was approved by referendum on 19 October 2002 (sometimes known as the Nice II referendum) and signed into law on 7 November of the same year. The amendment followed a previous failed attempt to approve the Nice Treaty which was rejected in the Nice I referendum held in 2001.

The Twenty-sixth Amendment was the second attempt of the Irish government to have the Treaty of Nice approved in a referendum. The purpose of the treaty was to amend the founding treaties of the European Union (EU). The previous attempt to approve the treaty was the Twenty-fourth Amendment Bill, which was rejected by voters in 2001. One of the arguments made against the Treaty of Nice in 2001 was that it might compromise the Republic's traditional neutrality. For this reason as well as permitting the state to ratify the Treaty of Nice, the Twenty-sixth Amendment added to the constitution a new provision, Article 29.4.9, guaranteeing that the state would not enter an EU mutual defence pact. The Twenty-sixth Amendment was introduced by the Fianna Fáil–Progressive Democrats coalition government of Bertie Ahern and was also supported by Fine Gael and the Labour Party (the two major opposition parties). However it was opposed by a number of other groups, including Sinn Féin, the Green Party and the Socialist Party. Voting in the referendum went 62.9% in favour and 37.1% against. The turnout was 49.5%, compared to the 34.8% turnout in the 2001 referendum

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