"If the US continues to use [MCAS Futenma], it may give rise to anti-base protests against all US military bases in Okinawa, or even an overall anti-US movement like what was seen in the past," Tamaki noted, recalling the turbulent days of the early 1970s when Japanese demonstrators unified under an anti-American stance.
"If that happens, such movements would have a significant impact on the Japan-US Security Arrangements as well as the Japan-US Alliance including operation of Kadena Air Base and White Beach Naval Facility."
Tamaki further noted in the letter that US Marine air operations should be removed completely from the island, since the US has the capability to handle any possible threats from China or North Korea with its Air Force and Navy.
Most notably, in December 1970, tensions came to a boil in Okinawa after an intoxicated American driver struck an Okinawan pedestrian, triggering one of the largest anti-US demonstrations. That incident, later known as the Koza Riots, saw thousands of Okinawans protest against the American presence on the island.
According to the Japan Times, local residents pulled American drivers from their cars, beat them and set their vehicles ablaze. More than 80 cars were left burning, and dozens of Americans were hospitalized.
Bruce Lieber, a veteran once assigned to the 20th Military Police Company in Okinawa, told the Times that he had been one of the first individuals on the scene. "It was really frightening. The crowd surrounded us, then they flipped our car and set it on fire," he recalled.
Despite the years since the Koza Riots, tensions have continued to simmer. Locals have repeatedly called for US officials to close down the Futenma base due to environmental concerns, repeated aerial mishaps and violent incidents perpetrated by US servicemembers.
In 2017, a helicopter window from a CH-53E Super Stallion became detached and landed on the sports field of an elementary school, where dozens of students were playing at the time. Sputnik reported that one student suffered a minor injury as a result.
Over the last several years, US and Japanese officials have drawn up various plans to relocate the service's base to Henoko Bay in the Okinawan city of Nago. However, the project has been repeatedly postponed due to opposition from local officials and residents who want the base removed from the prefecture.
According to Stars & Stripes, the relocation plan was expected to be completed by 2014. Landfill work for the base was recently resumed in December 2018 — a decision which was made before an island-wide referendum saw 70% of Okinawans vote against the relocation.
Updated estimates for the project suggest the base could be completed sometime between 2025 and 2026, if not later, the military website reported.