Tensions are running high between China and Japan other a small series of uninhabited islands in the East China Sea, known as the Senkakus in Japan and the Diaoyu in China and Taiwan. You can read more about the history of the island dispute here.
What may be especially worrying to American readers is the idea that US troops could get involved if an armed conflict did escalate. Japan is a key US ally, after all, though any kind of military conflict (especially with a military giant and trade ally like China) would clearly not be in US interests.
The key legal document here is the Treaty of Mutual Cooperation and Security from 1960 (you can download a pdf version of the treaty here). The treaty was signed to increase military cooperation between the US and Japan after the end of the post WWII occupation.
Yesterday, at a meeting of a U.S. Senate Foreign Relations subcommittee, Kurt Campbell, assistant secretary of state for East Asian and Pacific Affairs, said the Senkaku / Diaoyu islands were "clearly" covered by the treaty, Reuters reports.
"We do not take a position on the ultimate sovereignty of these islands," Campbell said, but later added "We do acknowledge clearly ... that Japan maintains effective administrative control ... and, as such, this falls clearly under Article 5 of the Security Treaty."
China has previously opposed the application of the treaty to the islands, according to Xinhua.
Here's the text of Article 5:
Each Party recognizes that an armed attack against either Party in the territories under the administration of Japan would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional provisions and processes.
Any such armed attack and all measures taken as a result thereof shall be immediately reported to the Security Council of the United Nations in accordance with the provisions of Article 51 of the Charter. Such measures shall be terminated when the Security Council has taken the measures necessary to restore and maintain international peace and security.
As you can see, Article 5 does clearly request that the matter first be taken to the UN Security Council, but it shows why US observers are getting worried.
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