Would the International Court of Justice be an appropriate venue for deciding the sovereignty of Taiwan?

The US District Court in Washington D.C. would be the appropriate tribunal. The question of Taiwan's sovereignty is a matter to be decided in the US Courts.

The International Court of Justice in the Hague http://www.icj-cij.org/ is not the appropriate venue for deciding on such issues, because Taiwan is not an independent sovereign nation, it is occupied territory of the United States of America.

Where is Taiwan's territorial sovereignty? It certainly hasn't disappeared!!! According to the legal logic in the Insular Cases of the US Supreme Court (beginning 1901), the sovereignty of an area under military occupation is held in trust by the (principal) occupying power in the form of a fiduciary relationship.

For Taiwan, the "conqueror" and "principal occupying power" is the United States of America.

Military government is the form of administration by which an occupying power exercises governmental authority over occupied territory. The necessity for such government arises from the failure or inability of the legitimate government to exercise its functions on account of the military occupation, or the undesirability of allowing it to do so.

By referring to the post-war San Francisco Peace Treaty of April 28, 1952, we note that Article 23a specifies the USA as the principal occupying power. Article 4b specifies that United States Military Government (USMG) jurisdiction over Taiwan is active. Taiwan is therefore occupied territory of the USA until USMG is legally supplanted.

To date, the US commander in chief has not announced the end of USMG jurisdiction over "Formosa and the Pescadores." In other words, the US federal government has never recognized any "civil government" operations (of any country) in Taiwan which have supplanted USMG.

No. It would not.

The UN is not an arbiter of sovereignty. The ICJ is used when one state has a greivance with another.

Only internationally recognized treaties have the rule of law in determining sovereignty. If you want to know the who holds the sovereignty of a territory, just look at the relevant treaty and you will find your clear answer.

That treaty would be the San Francisco Peace Treaty of 1952. Japan ceded Taiwan and the US is the principal occupier.

The Taiwan Cession's sovereignty is being held by the US until an appropriate civil government exists for the US to sign it over to.

The US has the power to sign it to whoever it wants, it even has the power to make it the 51st state of the union if it so desires.

The US is just trying to keep the psychos who are running the PRC from having a snit fit, so they pretend like Taiwan's status is some kind of mystery or something. This shows a scandalous lack of moral courage on their part.

Sovereignty would not be an issue for the International Court of Justice under the treaty establishing the court.

De jure sovereignty is a matter for the world community -- either other nations recognize Taiwan as sovereign or they don't. Traditionally, Taiwan has been part of China and until recently claimed to be the legitimate government of China. For Taiwan to get recognition as a separate sovereign, they would first have to formally declare independence (and then hope that someone comes to their defense when the PRC invades to crush the independence movement).

De facto (despite the claims of the governments of both the ROC and the PRC), Taiwan has been a separate sovereign for the past 57 years.

Assuming Taiwan could even get a case.. China could simply veto any attempts to enforce a ruling.

Why not just ask the people of Taiwan??

Doesn't matter one way or the other. China would not accept any outcome but one that rules in their favor.