Liechtenstein has a monarch as Head of state, and an elected parliament that enacts the law. It is also a direct democracy, where voters can propose and enact constitutional amendments and legislation independently of the legislature. The Constitution of Liechtenstein was adopted in March 2003, replacing the 1921 constitution. The 1921 constitution had established Liechtenstein as a constitutional monarchy headed by the reigning prince of the Princely House of Liechtenstein; a parliamentary system had been established, although the reigning Prince retained substantial political authority.