 The Basque Parliament' plenary approved it on 30 December 2004 by 39 votes with 35 against.The plan would have affected the Spanish Constitution, so the proposal was sent to the Spanish Parliament in January 2005 for debate ahead of a vote.The two main Spanish parties, the Socialists and the Conservatives, attempted to block the Basque parliament's decision by challenging it in the Constitutional Court, which approved the draft project for Spanish parliamentary consideration by a narrow margin.