Japan's Supreme Court has rejected an appeal by the Okinawa governor against a ruling that paved the way for the state to override the local government and begin landfill work on a controversial U.S. military base transfer.

The decision, dated Thursday, is likely to be seen as an endorsement for the central government to continue its work to reinforce soft ground at the relocation site for U.S. Marine Corps Air Station Futenma within the southern island prefecture.

The central government and Okinawa Prefecture have long been at odds over the transfer of the Futenma base from the densely-populated Ginowan to the Henoko coastal area in Nago. Okinawa has hosted the majority of U.S. military facilities in Japan since World War II ended in 1945.

Photo taken from a Kyodo News plane on Dec. 8, 2023, shows the Henoko coastal area in Nago, Okinawa, the site for the relocation of U.S. Marine Corps Air Station Futenma from another part of the southern Japanese island prefecture. (Kyodo)

The top court has now finalized the ruling by the Fukuoka High Court's Naha branch in December that ordered Okinawa Gov. Denny Tamaki to approve a modified plan for landfill work to relocate a key U.S. base within three weekdays.

Following the ruling, Tamaki ignored the high court's order for him to approve the plan, prompting the central government to intervene and grant approval on his behalf. In early January, the Defense Ministry began the landfill work.

The five justices of the Supreme Court were unanimous in concluding there was no reason to accept the final appeal, but they did not offer further details about their judgment.

Tamaki, who first became Okinawa governor in 2018 campaigning on a pledge to stop the transfer of the Futenma base, criticized the decision.

"I had expected a fair judgment in their capacity as 'guardians of the law.' It is extremely regrettable that the judiciary has thrown out the case without putting forward a tangible decision," he told reporters in Naha after the ruling.

Agreement on the relocation plan was reached with the United States in 1996, with Henoko chosen in 1999 by the Japanese government. However, opposition from Okinawa residents and political wrangling have delayed the plan for years.

In 2013, then Okinawa Gov. Hirokazu Nakaima approved the central government's request for landfill work to build a replacement facility in Henoko, but his successor, Takeshi Onaga, revoked the approval in 2015.

The Supreme Court later ruled the retraction unlawful, paving the way for landfill works to start in 2018. However, the discovery of soft ground at the reclamation site led the Defense Ministry to apply for a change in the construction plan in 2020.

Tamaki did not approve the request, citing insufficient research as the reason.

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