The new Guidelines for the US-Japan Defense Cooperation represent the most sweeping changes in the US-Japan alliance in the 55 years since the mutual security treaty was signed in 1960. Indeed, it is possible now to write about the alliance without putting the word in quotation marks.

The new guidelines, the first revision since 1997, are designed to spell out the duties and expectations of both countries in the event of war. They were announced during Prime Minister Shinzo Abe’s recent trip to the US and are synchronized with enabling legislation to be submitted soon to parliament.

They put into effect the Abe cabinet’s mid-July decision to “reinterpret” Japan’s pacifist constitution to permit “collective defense,” defined as being able to come to the defense of a treaty ally, like the US, or another country in which Tokyo has close relations, such as Australia.

Japan thus emerges as a potential partner in roles that were previously thought to be taboo, such as assisting the US military in situations and places that are not concerned with a strict defense of the Japanese home islands.

The new guidelines remove geographical restraints on military cooperation, meaning they could extend to the South China Sea and as far west as the Indian Ocean and the Persian Gulf on the idea that any interruption of shipments of petroleum from the Middle East represents an existential threat to Japan.

“The alliance will respond to situations that will have an important influence on Japan’s peace and security. Such situations cannot be defined geographically, the document says.

The first guidelines were written in 1978 when the world looked a lot different from today. At that time, the guidelines were influenced by Cold War worries, such as an outright invasion by the former Soviet Union.

That fear faded with the end of the Cold War (save for a mysterious increase in Russian bomber probes near Japan) to be replaced by other fears, including a potential Chinese invasion of Taiwan and North Korea’s determination to build nuclear weapons and put them on ballistic missiles.

The latest revisions, of course, focus more on China’s growing military not to mention the ongoing concerns about North Korea’s nuclear intentions. It also considers threats not envisioned in 1997 such as cyberwar and space.

The guidelines were never a static thing. The 1997 set did not anticipate the refueling missions in the Indian Ocean supporting the allied campaign in Afghanistan, anti-piracy patrols in the Gulf of Aden, or dispatch of an engineering battalion to Iraq.

Each of these actions, however, required enactment of separate legislation in Japan’s Parliament. Among other pending defense legislation is a new law that would obviate the need to get a separate law passed for each deployment. This is what the Americans seem to have in mind when they talk about “seamless” implementation of the guidelines.

With a nod to North Korea’s growing threat, Japan is to have primary responsibility for ballistic missile defense. This would include any North Korean intercontinental ballistic missile assault on American “assets” (the term is not specifically defined) such as bases in Guam and the US mainland. Pyongyang’s missiles cannot reach the US without first passing over Japan.

One of the anomalies that a strict reading of the Japanese constitution that collective defense is supposed to correct would be the ability to shoot down a missile headed for another ally, such as the US, or close partner, not just aimed at Japan itself.

The guidelines foresee certain “gray-area” contingencies which fall short of an outright attack on Japan territory, such as Chinese commandoes infiltrating some of Japan’s southern-most islands disguised as fishermen. Generally, Japan would take the lead in protecting its own territory with the US providing logistics support and intelligence.

Another gray-zone situation involves minesweeping. The US, which tends to neglect maritime mine warfare for more sexy military hardware like aircraft carriers, is eager to meld its minesweepers with Japanese formidable mine warfare forces. Presumably they could be deployed to the Strait of Hormuz in the event of war with Iran.

The Japanese Maritime Self Defense Force (navy) swept Iraqi mines in the northern Persian Gulf in the aftermath of the 1991 Gulf War, but this took place only after a ceasefire was signed. Under the new guidelines they could do this in the middle of hostilities.

The guidelines further state that the two countries will cooperate closely with each other on measures to maintain the traditional maritime order based on international law, including freedom of navigation. This would potentially put Japan squarely in the South China Sea imbroglio.

It is clear that Washington sees the new US Japan alliance turning into something like the US-British relationship. President Barack Obama said something like this when he singled out the country’s efforts to uproot the Islamic State during the joint press conference after their meeting in April with the implied suggestion that Japan might take part.

But the US may be expecting too much from this “new alliance.” Don’t expect to see Japanese air force F-15s fighter-bombers flying interdiction sorties over northern Iraq and Syria any time soon.

The new framework for national security “seems to be arousing excessive expectations,” said Takeshi Iwaya, a member of parliament who has been involved in the complex negotiations with the coalition partner Komeito in formulating the new defense legislation.

Komeito is much more pacifistic than the prime minister’s Liberal Democratic Party and insisted on some institutional brakes on any commitments of Japanese forces outside their own territorial waters as the price for supporting the new defense framework.

The Japanese public at large is worried lest their country be dragged into supporting American adventures in the Middle east, which is why public opinion polls show a populace divided but generally wary of Prime Minister Abe’s actions on defense.

It is a risky path for Abe too, as the first fatality from this new alliance would be so shocking to the Japanese public that it might bring down the government.