In the case of a “Taiwan contingency,” in which an armed conflict erupts between China and Taiwan, multiple patterns of action are expected to be taken by Japan’s Self-Defense Forces (SDF) according to the seriousness of the situation. The national security legislation that took effect in 2016 has expanded the scope of the SDF’s operations.
Taiwan is located close to the Nansei Islands, which include the Senkaku Islands in Okinawa Prefecture. So the government is concerned about the risk of a Taiwan contingency developing into a military attack on Japan.
If a contingency breaks out, the U.S. military may come to the military defense of Taiwan. In this case, the first possible scenario is that the SDF provides backup logistic support to the U.S. military, such as refueling, based on the law on situations that could have a serious impact on Japan’s peace and security, one piece of the security legislation.
Specifically, a Taiwan contingency needs to be recognized as falling under a “situation that has a serious impact” on Japan’s peace and security, such as posing the risk of a direct military attack on Japan if left unaddressed.
If the situation worsens, it could be deemed a “situation that poses a threat to Japan’s existence,” which allows Japan to fight by using armed force based on the limited right to collective self-defense. This was also made possible by the security legislation. But the Self-Defense Forces Act clearly stipulates that this only applies to a situation “when there is a clear risk of a threat to Japan’s existence and the risk of the fundamental overturning of Japanese people’s lives and rights.” So the government is expected to give this careful consideration.
In case of an armed attack on Japan, including an attack on a U.S. military base, or in case there is a clear and imminent danger of such an attack, the government can recognize these as a “situation of armed attack” and launch counterattacks by the use of force based on the right of individual self-defense.
Dispatching the SDF in these three situations requires Diet approval.