According to the 1999 Constitution of Niger, the President may call a referendum on any matter (except for a revision of those elements of the Constitution outlined in Article 136—including the presidential term limits). The Constitutional Court of Niger and the National Assembly of Niger must advise the president, but there is no provision that the president must heed their advice. On 25 May 2009, the Constitutional Court, made up of appointed judges, released a ruling that any referendum to create a new constitution would not only be unconstitutional, but would violate the oath Tandja had sworn on the Qur'an (a serious matter in this overwhelmingly Muslim country). The week prior, two major parties had come out in their opposition to the referendum proposal as well. On 13 May, the ANDP-Zaman Lahiya, led by Moumouni Adamou Djermakoye, declared its opposition to any change in the constitution. On 15 May the CDS-Rahama, the party without which the MNSD could not have formed governments in 1999, 2004, and 2007, came out opposing the referendum, and calling the constitution unalterable. Neither party moved into the opposition, and both Ousmane and Djermokoye said they were willing to negotiate with the president.