So...
Imagine this scenario: a lightly armed U.S. Navy intelligence-gathering ship cruising off the coast of North Korea is suddenly surrounded by enemy patrol vessels demanding it surrender. Only a few kilometers away a destroyer belonging to the Japanese Maritime Self-Defense Force (hereinafter called the navy) happens to be cruising close enough to offer help.
The prime minister must make a quick and agonizing decision: Does he order the destroyer to the rescue of a friendly vessel in harm's way, thereby violating the constitution, breaking the law and possibly exposing the ship's captain to criminal charges if any North Korean is killed? Or, should he obey the law, restrain the captain and thereby almost certainly destroy the alliance with its main protector beyond repair?
This kind of scenario that lies behind the renewed push to pass necessary changes to the Self-Defense Forces Act to permit it to engage in what's called "collective self-defense." Briefly, it refers to country coming to the aid of an ally when it is under attack and the party is in a position to help out. For years the government has interpreted collective defense as going against the country's war-renouncing constitution.
See, the Great Satan/Nippon Hookup security arrangement is often called an "alliance." It is not; the term alliance is purely a courtesy title. The so-called alliance is in essence a deal. The U.S. promises to defend Japan if attacked, with nuclear weapons if necessary (the nuclear umbrella). In return, Japan agrees to permit American bases on its soil for Americans to use basically as they see fit.
Japan is not obliged to defend the U.S. if she comes under attack. The most commonly mentioned scenario -- intercepting a North Korean intercontinental ballistic missile fired over Japan on the way to the U.S. mainland -- is considered by most observers as far-fetched. The "Pueblo scenario," rendering assistance to U.S. Navy ships if needed, is a far more likely contingency
The main emphasis behind a push to approve collective defense is Japan's rapidly expanding involvement in United Nations Peacekeeping Operations (PKO). In the past 20 years, more than 8,000 Self-Defense Force troops have been involved in PKOs in half a dozen countries. Engineering troops are currently stationed in South Sudan, and army medical personnel have helped in earthquake-ravaged Haiti. The navy takes part in anti-piracy patrols in the Gulf of Aden.
The 2007 changes to the Self Defense Forces Act made participating in UN-approved peace operations one of the main missions but did not solve such issues as lending assistance to other nations participating in the joint operations. Japan cannot now come to the assistance, say, of an NGO targeted by terrorists, for example, or to a non-Japanese ship attacked by pirates based in Somalia.
Currently, two special committees have been convened to consider aspects of Japan's security posture looking forward. They are expected to make their recommendations later this year and introduced to the Diet next year. One is the Advisory Panel on Reconstruction of the Legal Basis for Security, dealing with the collective defense issue. The other is Advisory Panel on National Security and Defense Capabilities.
Pic - "Rising Sun"