Article 12(2) of the UN Convention on the Rights of Persons with Disabilities guarantees persons with disabilities ‘the right to legal capacity on an equal basis with others in all aspects of life.’ In its General Comment on Article 12, the Committee on the Rights of Persons with Disabilities claims that this guarantee necessitates the abolition of the world's dominant approach to mental capacity law. According to this approach, when a person lacks the mental capacity to make a particular legal decision at the material time, the state authorises a third‐party to make it on her behalf. The Committee declares such substituted decision‐making a violation of the Convention's guarantee of legal capacity on an equal basis, and therefore demands it be replaced by an allegedly non‐discriminatory alternative called supported decision‐making. This article argues that we should reject the Committee's demand in its current form, because the most influential version of the new approach to supported decision‐making suffers from serious conceptual flaws that make it inferior to the mental capacity approach. However, I then argue that the Committee's demand stems from a legitimate ethical concern with respect and equality that ought to inform the CRPD's implementation process.