China-Taiwan Threats of Force and the Paradox of the ‘Nuclear Weapons Principle’

The People’s Republic of China (‘China’) has adopted legislation threatening to invade the Republic of China (‘Taiwan’) if the latter declares independence. Threats of force are prohibited by the UN Charter Article 2(4) and equivalent customary international law. This article proceeds along two apparently contradictory strands. On the one hand, the prohibition probably does not apply to non-State entities such as the Republic of China. One the other hand, the ICJ stated in the Nuclear Weapons opinion that ‘if the use of force itself in a given case is illegal […] the threat to use such force will likewise be illegal’. If the Republic of China declares independence it will become a State, making a PRC invasion illegal. Therefore, the PRC’s current threats should also be illegal. The best way to resolve this apparent paradox is to say that the ICJ’s ‘Nuclear Weapons principle’ must be nuanced.