Following the Orange Revolution and the 2004 presidential elections in December 2004 Ukrainian parliament adopted significant changes (amendments) to the Constitution of Ukraine by introducing concepts of political coalition, coalition government, imperative mandate as well as transferred some power from the President to the parliament, making Ukraine a parliamentary-presidential democracy. Those amendments were to enter into force on 1 January 2006. The new constitutional amendment also abolished single member-districts and replacing them with an increased multi-member proportional representation. According to the election law and the system adopted, the political parties or election blocs need to collect at least 3% of the national vote in order to gain seats in parliament.