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.

Its key features include: 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.

[8][9] 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".

[10] Article 1 of the Constitution of Japan (日本国憲法, Nihon-koku kenpō) defines the Emperor (天皇, Tennō)[11] to be "the symbol of the State and of the unity of the people".

The chief of the executive branch and head of government, the Prime Minister (内閣総理大臣, Naikaku Sōri-Daijin), is appointed by the Emperor as directed by the National Diet.

Individual leadership can significantly impact the policymaking process, especially following recent cabinet reforms that enhanced the prime minister's influence.

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.

Given the tendency for real negotiations in Japan to be conducted privately (in the nemawashi, or root binding, process of consensus building), the shingikai 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.

The most important deliberation council during the 1980s was the Provisional Commission for Administrative Reform, established in March 1981 by Prime Minister Suzuki Zenko.

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.

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.

Political parties had begun to revive almost immediately after the Allied occupation began because of surrender of Japan in World War II.

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.

This divisiveness in conservative ranks gave a plurality to the Japan Socialist Party, which was allowed to form a cabinet, which lasted less than a year.

A debate over limitations on military spending and the sovereignty of the Emperor ensued, contributing to the great reduction in the Liberal Party's majority in the first post-occupation elections (October 1952).

It was followed closely in popularity by the Komeito, founded in 1964 as the political arm of the Soka Gakkai (Value Creation Society), until 1991, a lay organization affiliated with the Nichiren Shōshū Buddhist sect.

Like the Japan Socialist Party, it favored the gradual modification and dissolution of the Japan-United States Mutual Security Assistance Pact.

The three-party coalition made up of the LDP, New Komeito, and the New Conservative Party maintained its majority in the Diet following the June 2000 Lower House elections.

On 24 April 2001, riding a wave of grassroots desire for change, maverick politician Junichiro Koizumi defeated former prime minister Hashimoto and other party stalwarts on a platform of economic and political reform.

On 8 August 2005, Prime Minister Junichiro Koizumi called for a snap general election to the lower house, as threatened, after LDP stalwarts and opposition DPJ parliamentarians defeated his proposal for a large-scale reform and privatization of Japan Post, which besides being Japan's state-owned postal monopoly is arguably the world's largest financial institution, with nearly 331 trillion yen of assets.

On 26 September 2006, the new LDP President Shinzo Abe was elected by a special session of the National Diet to succeed Junichiro Koizumi as the next prime minister.

On 11 January 2008, Prime Minister Yasuo Fukuda forced a bill allowing ships to continue a refueling mission in the Indian Ocean in support of US-led operations in Afghanistan.

[21] Noda dissolved the lower house on 16 November 2012 (as he failed to get support outside the Diet on various domestic issues i.e. consumption tax, nuclear energy) and general election was held on 16 December.

[23] With the changing political situation, earlier in November 2014, Prime Minister Abe called for a fresh mandate for the Lower House.

In an opinion poll the government failed to win public trust due to bad economic achievements in the two consecutive quarters and on the tax reforms.

Shinzō Abe was sworn as the 97th prime minister on 24 December 2014 and would go ahead with his agenda of economic revitalization and structural reforms in Japan.

[29] On 28 August 2020 following reports of ill-health, Abe resigned citing health concerns, triggering a leadership election to replace him as prime minister.

[31] After winning the leadership of the governing Liberal Democratic Party (LDP), Chief Cabinet Secretary Yoshihide Suga, a close ally of his predecessor, was elected as the 99th prime minister of Japan on 16 September 2020.

[35][36] On 8 July 2022, former prime minister Shinzo Abe was shot and killed at a campaign rally in Nara for the 2022 Japanese House of Councillors election.

[38] On 1 October 2024, Japan’s parliament confirmed Shigeru Ishiba, new leader of the ruling Liberal Democratic Party (LDP), as the new prime minister to replace Fumio Kishida.