The July 23 arrival of MV-22 Osprey tilt-rotor transport aircraft at U.S. Marine Corps Air Station Iwakuni in Yamaguchi Prefecture and plans to deploy them this fall to Okinawa have fueled stiff opposition from local governments nationwide.

Washington and Tokyo see the deployment of the aircraft, which hovers like a helicopter and flies like an airplane, as necessary to carry out America’s obligations under the U.S.-Japan Security Treaty.

But for local governments, the way Tokyo is handling the issue is a symptom of deeper problems with the U.S.-Japan Status of Forces Agreement, the legal framework U.S. military personnel operate under within Japan.

What’s the difference between the U.S.-Japan Security Treaty and the U.S.-Japan Status of Forces agreement?

The security treaty spells out general U.S. defense obligations on territories under Japanese administration in general terms, but does not oblige Japan to come to the defense of the United States. Contained within the treaty is Article VI, which grants the U.S. armed forces the right to use facilities and areas in Japan, and agrees their status shall be covered by the separate Status of Forces Agreement.

The SOFA, which was signed in 1960 along with the security treaty, details what U.S. forces are allowed to do.

Under the SOFA, what rights and restrictions are U.S. service members subject to?

In addition to having facilities provided by Japan, the SOFA exempts U.S. armed forces from Japanese passport and visa laws and regulations, although they must show a special photo ID if requested by Japanese authorities. They do not have to pay income tax to Japan. They are also not allowed to participate in any “political activities” while stationed in Japan.

Why are traffic accidents involving U.S. forces personnel a major cause of friction, especially in Okinawa?

Prefectural and municipal governments where U.S. bases are situated take exception to the SOFA’s Article X, which allows U.S. service members and civilians working for the military, as well as dependents of U.S. military personnel to drive in Japan without a Japanese license or even first taking a driving test in the country. All they need is a U.S. driver’s license or U.S. military-issued driving permit. This may have led to unnecessary accidents and deaths.

For local governments, what’s the most contentious aspect of the SOFA?

Article 17, which gives the U.S. military the right of jurisdiction over members of the U.S. forces or civilians working for them if they break Japanese laws while engaged in their official duties, has always been a thorn in the side of the police, who have long complained about a lack of cooperation when it comes to questioning U.S. military-linked people suspected in involvement in serious crimes.

In January 2011, Rufus J. Ramsey II, a U.S. civilian working at Camp Foster in Okinawa, was driving home after he’d clocked out when he had a head-on collision with Koki Yogi, 19, who was killed. At the time, the U.S. still considered the driver on official duty, however, and used Article 17 to prevent him from being prosecuted in a Japanese court. However, in November, an agreement was reached that would allow Japan to have jurisdiction over “serious” crimes like fatal traffic accidents, but only if the U.S. side first decides not to pursue criminal charges.

The case created outrage in Okinawa, and Washington and Tokyo found themselves under intense pressure to revise the SOFA. Instead, the U.S. and Japan issued a memorandum in November that included two agreements.

First, if a member of the armed forces or a military-linked civilian is caught by Japanese police while driving drunk, regardless of whether they are on or off duty, they lose their status under SOFA and Japan has primary jurisdiction.

Second, because civilian workers are not subject to the U.S. Uniform Code of Military Justice, they cannot be tried in a U.S. military court. They must be tried in a civilian court, and some can be taken to the U.S. to be tried in a civil court.

But if U.S. authorities judge that to be logistically impossible, the U.S. may decline to prosecute. At that point, under the November agreement, Japan can formally request to try the case, and the U.S. is supposed to grant sympathetic consideration.

Why is the U.S. apparently reluctant to turn over military and civilian workers if they’re suspected of committing a crime?

That depends on who you ask. Some view the determination of the U.S. to keep sovereignty over its military personnel as proof that it does not want an equal partnership with Japan.

U.S. legal experts note there are fundamental differences in U.S. and Japanese law that make simply turning over a U.S. service member to Japanese police problematic. Many of the Miranda rights, which police must tell the suspect upon arrest and are an integral part of America’s legal system, are not applicable to people arrested in Japan on criminal charges.

The U.S. also has concerns about the fact that suspects in Japan can be detained for up to 23 days without being formally charged, and can be denied access to legal counsel.

What about sovereignty?

Buried deep within the SOFA is an agreement that says Japanese authorities are not normally allowed to exercise the right of search, seizure or inspection with respect to any people or property within the facilities and area in use by and guarded under the authority of the U.S. armed forces or with respect to property of the U.S. armed forces wherever situated.

If Japanese police want to search, seize or inspect people or property of the U.S. armed forces, they have to get permission.

So under the SOFA, the Japanese government doesn’t have jurisdiction if, say, a U.S. plane or helicopter crashes off base?

This is a somewhat gray area.

In August 2004, a U.S. Marine Corps Sea Stallion helicopter crashed on the campus of Okinawa International University. Nobody was killed and no Japanese were injured, but controversy ensued when U.S. Marines from the adjacent Futenma base arrived, sealed off the crash site and refused to allow Okinawa police and firefighters access.

The issue raised the question of just where, under the SOFA, U.S. military sovereignty really ends and Japanese authority begins, and the response of the U.S. to the crash sparked anger in Okinawa, including among local officials who were not by nature against the bases.

As a result, the U.S. and Japan established new guidelines for off-base accident sites. Under the new rules, if an accident occurs outside a U.S. base, two perimeters will be set up. Japanese police will control the outer perimeter, and both the U.S. and Japan will be in charge of the inner perimeter, closest to the crash site. How both are to be defined remain unclear. However, the U.S. retains exclusive control over the crashed aircraft and the Japanese authorities have no control over their American counterparts at the site itself.

Has this solved the problem?

No. The U.S. and Japan keep agreeing to new guidelines, minutes and other documents in an effort to improve or refine the SOFA, but many Japanese want fundamental revisions.

Some, like former Okinawa Gov. Masahide Ota, have proposed specific language for a new agreement. In a 1995 letter to then U.S. President Bill Clinton, Ota proposed revisions to 10 of the agreement’s 26 articles. These included granting municipalities more authority to enter U.S. bases, subjecting U.S. military forces to stricter customs controls and, in cases where Japan exercises judicial authority, allowing, in all situations, Japanese police to take into custody U.S. military and related civilians who are criminal suspects.

Is there any pressure from the U.S. side to revise the SOFA?

Yes. In 2010, the U.S. House of Representatives passed what is known as a “sense of Congress” calling for revising the SOFA to assist U.S. military personnel whose children have been kidnapped by Japanese family members.

The document is not a legal instrument, but was designed to apply political pressure on U.S. President Barack Obama to press Japan on the issue.

The Weekly FYI appears Tuesdays. Readers are encouraged to send ideas, questions and opinions to hodobu@japantimes.co.jp