Hungary is a unitary, parliamentary, representative democratic republic. The Hungarian political system operates under a framework reformed in 2012; this constitutional document is the Fundamental Law of Hungary. Amendments generally require a two-thirds majority of parliament; the fundamental principles of the constitution (as expressed in the articles guaranteeing human dignity, the separation of powers, the state structure, and the rule of law) are valid in perpetuity. 199 Members of Parliament (''országgyűlési képviselő'') are elected to the highest organ of state authority, the unicameral ''Országgyűlés'' (National Assembly), every four years in a single-round first-past-the-post election with an election threshold of 5%.