How Japan is governed: a constitution written in a week that has never once been changed

What the constitution actually did

The 1947 constitution replaced the Meiji Constitution and inverted it.

Under the Meiji document the emperor held supreme political power and both the cabinet and the military answered to him rather than to the elected legislature. Under the new one, sovereignty is vested in the people, and the emperor's role is reduced to a defined phrase: the symbol of the State and of the unity of the people, exercising ceremonial functions only.

The structure is a parliamentary system with three branches: the National Diet as legislature, a Cabinet led by a prime minister as executive, and a Supreme Court and lower courts as judiciary. The Diet is declared the highest organ of state power and the sole law-making organ of the State. Individual rights are guaranteed directly: legal equality, freedom of assembly, association and speech, due process, fair trial.

Article 9 is the clause the world knows. Its first paragraph reads that, aspiring sincerely to an international peace based on justice and order, the Japanese people forever renounce war as a sovereign right of the nation and the threat or use of force as means of settling international disputes.

One detail of how it was adopted matters more than it looks. To preserve legal continuity, the new text was not enacted as a break with the old one. It was submitted as the Bill for Revision of the Imperial Constitution under Article 73 of the Meiji Constitution, formally an amendment to the document it replaced, sent to the Imperial Diet by imperial rescript on 20 June 1946.

Why it has never been amended

Amendment requires a two-thirds vote in both houses of the Diet and then approval in a national referendum. No amendment has ever cleared that.

The result is a supreme constitutional text that has stood unchanged since 1947, which is an unusually long run without alteration. Conservative and nationalist politics in Japan has pushed for revision, of Article 9 above all, for most of that period. Coalitions have occasionally held two-thirds of the lower house and have not held it in both chambers at the moments it would have mattered, and no revision has ever been put to the electorate.

So the constitutional argument in Japan takes an unusual form. Rather than amending the text, governments have reinterpreted it, and the most consequential decisions about Japanese defence policy have been made as questions of interpretation rather than as changes to the words.

What the war-renouncing clause means now

Despite renouncing the maintenance of military forces, Japan operates the Self-Defense Forces, reconstituted in 1954 at the request of the United States, and hosts a substantial United States military presence.

The way that came about is recorded in the drafting itself. During the passage of the bill through the House of Representatives in August 1946, the text of Article 9 was modified in committee, in what became known as the Ashida Amendment, and the renunciation of armed forces was the most contested part of the document even then.

The security relationship was fixed alongside the peace settlement. The San Francisco Peace Treaty of 1951 normalised relations with the United States, and the security treaty signed at the same time locked Japan into a military alliance and permitted American bases on Japanese soil. Those bases remain, concentrated on Okinawa, which was returned to Japanese sovereignty only in 1972, the Ogasawara Islands having been returned in 1968.

That arrangement has never been uncontested. The 1960 Anpo protests against revision of the security treaty brought millions onto the streets; the revision went through and the prime minister of the day resigned. Some Japanese have held from the beginning that the existence of the Self-Defense Forces violates Article 9 outright.

How the Diet works

The Diet has two elected chambers, and they are not equal.

The House of Representatives selects the prime minister, controls the budget, ratifies treaties, can force a government's resignation, and can override the upper house on legislation it has rejected. Because the prime minister can dissolve it, its members frequently serve less than a full term.

The House of Councillors cannot be dissolved and its members serve fixed six-year terms, which gives it independence and very little power. Bills reach it to be approved rather than made.

The override exists and is used sparingly enough to be an event. When a government used its lower-house majority in January 2008 to override an upper house controlled by the opposition, it was the first time in fifty years that the lower house had voted to ignore the upper.

As in most parliamentary systems, most legislation considered by the Diet is proposed by the cabinet, which relies on the bureaucracy to draft the actual bills. That is the quiet fact behind a great deal of Japanese political analysis: the permanent officials write the law.

How the electoral system was rebuilt

The first postwar general election was held in 1946, and it was the first in which Japanese women could vote.

The system that produced the long era of single-party dominance was itself replaced from within. When the governing party failed to win a majority in the lower house election of 18 July 1993, a coalition of new and existing opposition parties formed a government, and its principal legislative objective was reform of politics itself: new restrictions on political financing and major changes to the electoral system, passed in January 1994.

The lower house now elects members through two tiers, single-member districts and regional proportional blocks, and the interaction between the two is not always tidy. A party can win more votes than it has candidates to seat: in a recent election one party earned enough proportional support for fourteen further seats and had too few losing district candidates to fill them, so those seats passed to other parties across the Southern Kantō, Tokyo, Hokuriku-Shin'etsu and Chūgoku blocks. Another party forfeited two seats in the Kinki block because its district candidates had not reached the 10% threshold that makes a candidate eligible for a proportional seat.

Those are technical outcomes, and they matter because they show what the 1994 reform did. It replaced a system that rewarded factional competition inside one large party with one that rewards parties able to field credible candidates everywhere, and the arithmetic of the second tier now decides seats that the first tier could not.

What the courts can do

Judicial power is vested in the Supreme Court and the lower courts, in a civil law system.

The court holds the power of constitutional review, which is where the argument about Article 9 would ordinarily be settled in another country. In practice Japanese courts have been reluctant to decide questions the political branches have left open, and the constitutionality of the Self-Defense Forces has never been resolved by a ruling that closed the matter.

That reticence is the third leg of the arrangement described above. A constitution that cannot be amended, a legislature in which one chamber can obstruct and the other can override, and a judiciary that declines to rule on the largest constitutional question, together produce a system that changes by interpretation and precedent rather than by decision. It is stable, it is slow, and it leaves the biggest questions permanently open.

Why one party has governed so long

The Liberal Democratic Party was formed in 1955 out of a merger of conservative parties, and Japan has been governed by prime ministers from outside it only in 1993 to 1996 and 2009 to 2012.

That is close to seventy years of near-continuous rule by a single party in a functioning democracy with free elections, and it is the single most distinctive feature of Japanese politics. The system that produced it was set out early: the Yoshida Doctrine, named for the prime minister who guided Japan through the occupation, held that Japan should stay tightly aligned with the United States and concentrate on economic development rather than active foreign policy. Successive governments delivered growth, and growth returned governments.

Party politics did not begin there. Organisations revived almost immediately after the occupation began: the Japan Socialist Party and the Japanese Communist Party reestablished themselves, and the prewar conservative parties returned under new names before merging in 1955. The long era of single-party government is therefore a postwar settlement rather than an inheritance, and it took ten years of open competition to form.

The party's dominance has been dented rather than broken. The end of the bubble economy and a run of corruption scandals weakened its position from the 1990s, and it lost power twice, briefly each time.

What that record means is contested and worth stating carefully. It can be read as evidence of a party that has kept adapting, or of a system in which factional competition inside one party substitutes for competition between parties. Both readings describe the same election results.

How the country is administered

Below the national government sit 47 prefectures, the first level of jurisdiction, and they are not uniform.

There are 43 prefectures proper, ken; two urban prefectures, fu, being Osaka and Kyoto; one regional prefecture, dō, being Hokkaido; and one metropolis, to, being Tokyo, which is a merged city and prefecture with features of both.

Each prefecture has a directly elected governor and a unicameral assembly elected for four years, which enacts ordinances and budgets. Below them are cities, districts, towns and villages, and Hokkaido additionally runs fourteen subprefectural bureaus because of its size.

The prefectures are a Meiji creation and their origin explains their shape. The first ones were created in 1868 to replace shogunal administrators in territory the new government controlled directly. In 1871 every remaining feudal domain was converted into a prefecture, so that the system covered the whole country, and waves of consolidation produced the present 47 by the turn of the century. In many cases their boundaries follow the ancient provinces, which means a modern Japanese administrative map is legible against a map more than a thousand years old.

What remains unsettled

Three things about this system have been argued over continuously and none is close to resolution.

The first is Article 9, where the gap between the text and the Self-Defense Forces is bridged by interpretation rather than by amendment, and where any attempt to close it constitutionally must clear two-thirds of both houses and a referendum.

The second is the weight of the upper house, a chamber that cannot be dissolved, cannot originate much, and can nonetheless obstruct, which has produced periodic deadlock whenever the two chambers have diverged.

The third is the concentration of authority in the bureaucracy, which drafts the legislation that the cabinet proposes and which has outlasted every government of the postwar period. A constitution can specify that the Diet is the sole law-making organ of the State. It cannot specify who writes the drafts.