The ruling Liberal Democratic Party and its junior coalition partner, Komeito, have deepened their reliance on each other since forming an alliance two decades ago.

The LDP, Komeito and the now-defunct Liberal Party established a coalition government in 1999. The LDP and Komeito have cooperated in every election since, even during a rare stint when they were out of power for just over three years.

The partnership survives because the two parties have prioritized stable power over policy differences. But they are expected to face a difficult situation with regard to Prime Minister Shinzo Abe’s quest to revise the postwar pacifist Constitution.

The alliance “has given stability to politics in the Heisei and Reiwa eras,” Abe, who doubles as LDP president, told reporters on Oct. 4. “It is a ‘beautiful harmony’ enabling the parties to share their merits and complement each other,” he said, referring to the official English translation of Reiwa, which began on May 1.

Natsuo Yamaguchi, head of Komeito, which was founded by lay members of the Buddhist organization Soka Gakkai, said the alliance “has contributed to political stability and brought many achievements.”

In 1999, the fortunes of the tripartite coalition followed the severe setback dealt to the LDP the previous year in the Upper House election, creating a “twisted” body that lost its majority in the House of Councilors but retained control of the House of Representatives, the Diet’s powerful lower chamber.

After Prime Minister Ryutaro Hashimoto resigned in the wake of the election loss, his successor Keizo Obuchi persuaded Komeito to grant his plea for cooperation to smooth the management of parliamentary affairs. The Liberal Party joined the partnership to establish a three-way coalition government in October 1999.

After subsequent twists and turns, including the Liberal Party’s defection, the LDP and Komeito have managed to preserve their two-way alliance since 2003.

The partnership has continued for 20 years because of the parties’ solid alignment in elections.

The cooperation with Komeito is a boon to the LDP, with Soka Gakkai said to command 20,000 to 30,000 votes in each single-seat constituency. LDP candidates, backed by Komeito, commonly call on voters to support them in electoral districts and to support Komeito candidates in proportional representation districts.

But the LDP and Komeito differ on security policy.

A typical example was seen when they were drafting legislation to make it legal for Japan to exercise the U.N. right to collective self-defense, or coming to the aid of an ally under attack. The legislation aroused strong opposition from Soka Gakkai as being counter to the philosophy of Komeito being a “party of peace.”

Komeito eventually complied with the Abe administration’s decision to change the government’s interpretation for the Constitution instead to permit the limited use of collective defense.

Recently, Komeito has often buckled under pressure from the LDP, which has a strong presence in both houses of the Diet.

Down the road, the biggest focal point of the alliance will be Komeito’s stance on the constitutional amendments planned by the LDP.

The LDP has drawn up a set of proposals, including one to insert a mention of the Self-Defense Forces in war-renouncing Article 9 to clarify its legal status. Many members of Komeito feel a strong aversion to this amendment proposal because they fear it could damage the party’s banner.

“At stake is whether we (LDP and Komeito) can reach an agreement through discussions from a variety of viewpoints,” Yamaguchi said. “We should strive to deepen understanding while analyzing public reaction.”

But a senior Komeito member said Yamaguchi “in his heart wants to avoid the constitutional issue because he supports the current Constitution.” They said Komeito has no intention of making any concession on its stance of protecting the supreme code.

The party will likely be tested on its core values during the process of addressing these amendment proosals with the LDP.