The Twenty-eighth Amendment of the Constitution Bill 2008 (bill no. 14 of 2008) was a proposed amendment to the Constitution of Ireland that was put to a referendum in 2008 (the first Lisbon referendum). The purpose of the proposed amendment was to allow the state to ratify the Treaty of Lisbon of the European Union.
The amendment was rejected by voters on 12 June 2008 by a margin of 53.4% to 46.6%, with a turnout of 53.1%.[1] The treaty had been intended to enter into force on 1 January 2009, but had to be delayed following the Irish rejection. However, the Lisbon treaty was approved by Irish voters when the Twenty-eighth Amendment of the constitution was approved in the second Lisbon referendum, held in October 2009.