Kouchner is a well-known pro-European. He supported the ratification of the Lisbon Treaty when it was threatened to be rejected by the Irish in referendum. In the run up to the referendum in the Republic of Ireland on the ratification of the Treaty of Lisbon, Kouchner warned that any "No" vote towards the treaty would be detrimental to Ireland and the Irish economy. He also commented that "It would be very, very awkward if we were not able to count on the Irish, who have often counted on Europe". His comments were dismissed as "unhelpful" by leading Irish politicians, and some media commentators have suggested that his remarks may have galvanised the "No" campaign in the run up to the rejection of the Lisbon Treaty on 13 June 2008.