Liechtenstein is a constitutional monarchy ruled by the hereditary princes of the house of Liechtenstein. The monarchy is hereditary in the male line. The constitution of 5 October 1921, as amended in 1987, provides for a unicameral parliament (Landtag) of 25 members elected for four years. Election is by universal suffrage at age 18 and is on the basis of proportional representation. Women gained the right to vote in 1984. A new voting system that went into effect as of the 1974 national elections provides nine representatives for the Upper Land district and six representatives for the Lower Land district.
A new constitution was approved in March 2003, that grants the ruling prince extensive powers, including the right to veto legislation and to control the appointment of judges, in addition to the rights guaranteed to him under the former constitution.
The prince can call and dismiss the Landtag. On parliamentary recommendation, he appoints the prime minister, who must be of Liechtenstein birth, and the deputy prime minister for four-year terms. It is the regular practice for the prime minister to be of the majority party and the deputy prime minister to be selected from the opposition. The Landtag appoints four councillors for four-year terms to assist in administration. Any group of 1,000 persons or any three communes may propose legislation. Bills passed by the Landtag may be submitted to popular referendum. A law is valid when it receives majority approval by the Landtag and the prince's signed concurrence.