jats:titleAbstract</jats:title> jats:pMuch has been said about the shortcomings of the two-element test for customary international law, the traditional methodology on which the jats:scILC</jats:sc> has focused in its recently completed study on the identification of custom. But custom as a source of law is notoriously elusive and slippery, and the deficiencies of the traditional methodology, for which there is no easy fix, are a reflection of a decentralised international legal system lacking a legislature and a system of courts with compulsory jurisdiction. The article offers some thoughts on the character of the two-element approach as an evaluative test, and the functions that it performs in structuring and constraining international legal reasoning in a way that safeguards the equality of States. By reflecting on the methodology’s constructive role, the article cautions against overly alarmist predictions that customary international law is a dancefloor.</jats:p>