In addition to its legislative power, the National Assembly is the sole body in the country with constitutive power. (A number of other countries separate the two functions, e.g. through a Constituent Assembly.)
In adopting a constitution, the state places constraints on itself to ensure fundamental rights for its citizens, provides guarantees to respect and safeguard their freedom, and lays down a constitutional framework and forms for the exercise of power. Adopting and amending the constitution are legislative acts which require a two-thirds majority of all Members of Parliament.
The National Assembly adopted a new constitution, the Fundamental Law of Hungary, on 18 April 2011, which went into force on 1 January 2012 in conjunction with the Transitional Provisions of the Fundamental Law of Hungary.