Daddah declared the RFD to be "the country's biggest political force" after the first round of the 2006 Mauritanian parliamentary election, held on 19 November. The RFD participated in this election as part of an eight party opposition alliance. In Kiffa on January 12, 2007, Daddah announced his candidacy in the March 2007 presidential election. In the first round, held on 11 March, he won 20.69% of the vote, in second place behind Sidi Ould Cheikh Abdallahi, who won 24.80%. In the second round of the election, held on 25 March, Daddah was defeated by Abdallahi, taking 47.15% of the vote against Abdallahi's 52.85%. Daddah won in three of the country's 13 regions: in Nouakchott, in Inchiri Region, and in Trarza Region, where he is from. Daddah accepted the results and congratulated Abdallahi on his victory. On 30 May 2007, Daddah was designated as the official leader of the opposition by the Constitutional Court. Daddah and the RFD supported the military coup d'état of 6 August 2008. Speaking to Al Jazeera on 12 August, Daddah described the coup as "a movement to rectify the democratic process" and alleged that the 2007 presidential election was "marked by fraud". On 4 February 2009, while still expressing support for the coup and saying that Abdallahi should not be restored to the Presidency, Daddah proposed that the army give up power and that anyone who was serving in the military at the time of the coup should not be allowed to participate in the planned 2009 presidential election. He expressed concern that continued military rule would negatively affect Mauritania's relations with the rest of the world, potentially including economic sanctions. Daddah and the RFD chose to boycott the 2009 presidential election, decrying the junta's allegedly unilateral timetable. After the junta and the opposition reached an agreement and the election was delayed to 18 July 2009, the RFD announced on 9 June 2009 that Daddah had been designated as the party's presidential candidate by a special party congress.