In Japan, politics are conducted in a framework of a dominant-party bicameral parliamentary representative democratic constitutional monarchy. A hereditary monarch, currently Emperor Naruhito, serves as head of state while the Prime Minister of Japan, currently Sanae Takaichi since 2025, serves as the elected head of government.
Legislative power is vested in the National Diet, which consists of the House of Representatives and the House of Councillors. The House of Representatives has eighteen standing committees ranging in size from 20 to 50 members and The House of Councillors has sixteen ranging from 10 to 45 members.Philip Laundy - Parliaments in the Modern World page 109
Executive power is vested in the Cabinet, which is led by the Prime Minister who is nominated by National Diet and appointed by the Emperor. A Liberal Democratic minority government has held office since 2025.
Judicial power is vested in the Supreme Court and lower courts, and sovereignty is vested in the people of Japan by the 1947 Constitution, which was written during the Occupation of Japan primarily by American officials and had replaced the previous Meiji Constitution. Japan is considered a constitutional monarchy with a system of civil law.
The Japanese politics in the post-war period has largely been dominated by the ruling Liberal Democratic Party (LDP), which has been in power almost continuously since its foundation in 1955, a phenomenon known as the 1955 System. Of the 32 prime ministers since the end of the country's occupation in 1952, 25 as well as the longest serving ones have been members of the LDP.
Japan is currently a "full democracy" in the Democracy Index with the highest V-Dem electoral democracy score and the second highest liberal democracy score in Asia.
Constitution
The current constitution was approved by Japan in 1947, this document aimed to address the weaknesses of the previous Meiji Constitution and lay the foundation for a vibrant democracy in Japan. Its key features include:
Sovereignty of the People: According to the constitutions, the sovereignty rests with the people. Democratic institutions: The constitution reinstated democratic institutions that had flourished under Taisho democracy. Expanded Suffrage: The constitution of 1947 expanded suffrage to women guaranteeing equal rights for men and women. Parliamentary system: Japan adopted a parliamentary system of government, maintaining a lower house and an upper house, similar to its previous democratic experiences during the Taisho era. Labor rights: It introduced Western-type labor practices, including a clause that declared the right to collective bargaining. Peace clause: The article 9 of the constitution renounces war and prohibits the threat or use of force as means of settling international disputes.
Legitimacy The creation and ratification of this current document has been widely viewed by many geopolitical analysts and historians as one that was forced upon Japan by the United States after the end of World War II.
Although this "imposition" claim arose originally as a rallying cry among conservative politicians in favour of constitutional revision in the 1950s, and that it wasn't "inherently Japanese", it has also been supported by the research of several independent American and Japanese historians of the period.
A competing claim, which also emerged from the political maelstrom of the 1950s revision debate, holds that the ratification decision was actually the result of apparent "collaboration" between American occupation authorities, successive Japanese governments of the time, and private sector "actors".
Government
Article 1 of the defines the Professor Yasuhiro Okudaira notes a misnomer in the use of the word "Emperor" to describe the nation's living state symbol. In Okudaira's view, the word "Emperor" ceased to be applicable when Japan ceased to be an empire under the 1947 Constitution. "Thus, for example, the Imperial University of Tokyo became merely University of Tokyo" after World War II. He would apparently have the word tennō directly taken for English use (just as there is no common English word for "sushi". Yasuhiro Okudaira, "Forty Years of the Constitution and its Various Influences: Japanese, American, and European" in Luney and Takahashi, Japanese Constitutional Law (Univ. Tokyo Press, 1993), pp. 1–38, at 4. to be "the symbol of the State and of the unity of the people". He performs ceremonial duties and holds no real power. Political power is held mainly by the Prime Minister, Cabinet, and other elected members of the National Diet. The Imperial Throne is succeeded by a paternal male member of the Imperial House as designated by the Imperial Household Law.
The chief of the executive branch and head of government, the , is appointed by the Emperor as directed by the National Diet. The prime minister in Japan is the head of the cabinet, has the power to appoint and dismiss cabinet ministers, and can dissolve the lower house of the Diet. While formally limited in powers, the prime minister possesses informal powers such as party support, popularity, and influence over the bureaucracy. Individual leadership can significantly impact the policy-making process, especially following recent cabinet reforms that enhanced the prime minister's influence. The members are nominated by the Prime Minister, and are also required to be civilian. The country has a Liberal Democratic Party (LDP) minority government as of 21 October 2025, and it has been convention that the President of the LDP serves as the Prime Minister since 2012.
Legislature
Japanese constitution states that the , its law-making institution, shall consist of two Houses, namely the and the . The Diet shall be the highest organ of state power, and shall be the sole law-making organ of the State. It states that both Houses shall consist of elected members, representative of all the people and that the number of the members of each House shall be fixed by law. Both houses pass legislation in identical form for it to become law. Similarly to other parliamentary systems, most legislation that is considered in the National Diet is proposed by the cabinet. The cabinet then relies on the expertise of the bureaucracy to draft actual bills.
The lower house, the House of Representatives, the most powerful of the two, holds power over the government, being able to force its resignation. The lower house also has ultimate control of the passage of the budget, the ratification of treaties, and the selection of the Prime Minister. Its power over its sister house is, if a bill is passed by the lower house (the House of Representatives) but is voted down by the upper house (the House of Councillors), the ability to override the decision of the House of Councillors. Members of the lower house, as a result of the Prime Minister's power to dissolve them, more frequently serve for less than four years in any given terms.
The upper house, the House of Councillors, is very weak and bills are sent to the House of Councillors only to be approved, not made. Members of the upper house are elected for six-year terms with half the members elected every three years.
It is possible for different parties to control the lower house and the upper house, a situation referred to as a "twisted Diet", something that has become more common since the JSP took control of the upper house in 1989.
Political parties and elections
Several political parties exist in Japan. However, the politics of Japan have primarily been dominated by the Liberal Democratic Party (LDP) since 1955, with the Democratic Party of Japan (DPJ) playing an important role as the opposition for a lengthy period of time. The DPJ was the ruling party from 2009 to 2012 with the LDP as the opposition. The LDP was the ruling party for decades since 1955, despite the existence of multiple parties. Most of the prime ministers (presidents of the LDP) were elected from inner factions of the LDP.
House of Councillors
House of Representatives
Policy making Despite an increasingly unpredictable domestic and international environment, policy making conforms to well established postwar patterns. The close collaboration of the ruling party, the elite bureaucracy and important interest groups often make it difficult to tell who exactly is responsible for specific policy decisions.
Policy development in Japan
After a largely informal process within elite circles in which ideas were discussed and developed, steps might be taken to institute more formal policy development. This process often took place in deliberation councils (). There were about 200 , each attached to a ministry; their members were both officials and prominent private individuals in business, education, and other fields. The played a large role in facilitating communication among those who ordinarily might not meet.
Given the tendency for real negotiations in Japan to be conducted privately (in the , or root binding, process of consensus building), the often represented a fairly advanced stage in policy formulation in which relatively minor differences could be thrashed out and the resulting decisions couched in language acceptable to all. These bodies were legally established but had no authority to oblige governments to adopt their recommendations. The most important deliberation council during the 1980s was the Provisional Commission for Administrative Reform, established in March 1981 by Prime Minister Suzuki Zenko. The commission had nine members, assisted in their deliberations by six advisers, twenty-one "expert members," and around fifty "councillors" representing a wide range of groups. Its head, Keidanren president Doko Toshio, insisted that the government agree to take its recommendations seriously and commit itself to reforming the administrative structure and the tax system.
In 1982, the commission had arrived at several recommendations that by the end of the decade had been actualized. These implementations included tax reform, a policy to limit government growth, the establishment in 1984 of the Management and Coordination Agency to replace the Administrative Management Agency in the Office of the Prime Minister, and privatization of the state-owned railroad and telephone systems. In April 1990, another deliberation council, the Election Systems Research Council, submitted proposals that included the establishment of single-seat constituencies in place of the multiple-seat system.
Another significant policy-making institution in the early 1990s was the Liberal Democratic Party's Policy Research Council. It consisted of a number of committees, composed of LDP Diet members, with the committees corresponding to the different executive agencies. Committee members worked closely with their official counterparts, advancing the requests of their constituents, in one of the most effective means through which interest groups could state their case to the bureaucracy through the channel of the ruling party.
Opinion polls A 2026 Ipsos opinion poll found the most common political issues were inflation, low wages and taxation.
History Post-war Political parties had begun to revive almost immediately after the Allied occupation began because of surrender of Japan in World War II. Left-wing organizations, such as the Japan Socialist Party and the Japanese Communist Party, quickly reestablished themselves, as did various conservative parties. The old Rikken Seiyūkai and Rikken Minseitō came back as, the Liberal Party (Nihon Jiyūtō) and the Japan Progressive Party (Nihon Shimpotō) respectively. The first postwar general election was held in 1946 (women were given the franchise for the first time in 1946), and the Liberal Party's vice president, Yoshida Shigeru (1878–1967), became prime minister.