Multilateralism a la carte: the limits to unilateral withholdings of assessed contributions to the UN budget

Article 17 of the UN Charter establishes the duty of Member States collectively to provide financial support for the organisation, according to an apportionment scale decided by the General Assembly. Since the 1950s, certain members have unilaterally tried to challenge the duty to pay assessed contributions either on political or on legal grounds. This practice has recently posed serious threats to the financial viability of the UN because of selective withholding by the United States, the largest contributor to the UN. This paper argues that unilateral selective withholdings aimed at advancing national values or priorities have no basis in the Charter. However, unilateral withholdings may be admissible as a last resort remedy for Member States to protect themselves against possible ultra vires or illegal acts of UN organs. To prevent abuses of this remedy, its exercise should be limited to clear violations of the law and be conditioned by three criteria: a) specific necessity, b) integrity, and c) consistency. In the absence of a centralized system of judicial review in the UN, these criteria would help prevent and minimize abuses of the ultra vires claim.