[1][2][3][4][5] The amendment's enactment followed the failure of a previous attempt which was rejected in the first Lisbon referendum, held in June 2008.

[1] Following the referendum, Dáil Éireann (the lower house of parliament) gave its approval to the Treaty on 8 October 2009.

[7] These formalities having been conducted, the state ratified the treaty by depositing the instrument of ratification with the Italian government on 23 October.

The Treaty of Lisbon represents the European-wide political compromise that was agreed upon in the wake of the rejection of the Constitution.

EU member states later issued a set of guarantees to the Irish government, indicating that the Lisbon treaty would not effect changes regarding taxation, military activity, or abortion in Ireland,[11] which led to a second referendum Before the amendment, the wording of Article 29.4 of the Constitution of Ireland was: 2° For the purpose of the exercise of any executive function of the State in or in connection with its external relations, the Government may to such extent and subject to such conditions, if any, as may be determined by law, avail of or adopt any organ, instrument, or method of procedure used or adopted for the like purpose by the members of any group or league of nations with which the State is or becomes associated for the purpose of international co-operation in matters of common concern.

With the exception of some outlying islands that went to the polls two days ahead of the rest of the country, official voting took place on Friday, 2 October 2009 between 07:00 and 22:00.

[29] Tánaiste Mary Coughlan said the No vote across her home county, Donegal, was apparent from around a fortnight previously because of "mixed messages".

[29] President of the European Commission José Manuel Barroso said the vote ensured it was "a great day" for both Ireland and Europe.

[30] President of the European Parliament Jerzy Buzek stated that work would now get underway "to overcome the difficulties" that remained.

[30] Declan Ganley, Libertas leader, said the unexpectedly high Yes vote demonstrated "how scared people are" of the state of the economy.

[30] Nigel Farage, leader of the United Kingdom Independence Party, said the process had been no different from "a corrupt election in Zimbabwe or Afghanistan".

[30][34] Bruce Arnold, a columnist with the Irish Independent, said the damage done to the disenfranchised by the "tainted outcome" of the referendums would "not be easily fixed".