While universalist theories have come under increasing attack from relativist and post-modern critics, such as Walzer, MacIntyre and Rorty, Kantian constructivism can be seen as a saviour of universalist ethics. Kantian constructivists accept the criticism that past universalist theories were foundational and philosophically comprehensive and thus contestable, but dispute that universalist principles are unattainable. The question then arises if Kantian constructivism can deliver a non-foundational justification of universal principles. Rawls, the first Kantian constructivist, has seemingly retreated from the universalist ambitions (...) of Kantian constructivism. However, others have taken up the project of Kantian constructivism. One of them is O’Neill, who argues that she can succeed where Rawls failed and provide a truly universal non-foundational constructivism. Her requirements for such a constructivism are a constructive justification of the procedure of construction and the use of only abstract, non-ideal starting points. I will argue that O’Neill fails on both accounts. Instead of justifying the principle of practical reason constructively she gives an instrumental and therefore conditional justification. Instead of relying on purely abstract starting points her account builds on an underlying value assumption. This indicates inherent contradictions within constructivism, and might force defenders of universalism to look elsewhere to answer the relativist and post-modern critic. (shrink)