One of the more debated topics in the recent realist literature concerns the compatibility of realism and utopianism. Perhaps the greatest challenge to utopian political thought comes from Bernard Williams’ realism, which argues, among other things, that political values should be subject to what he calls the ‘realism constraint’, which rules out utopian arguments based on values which cannot be offered by the state as unrealistic and therefore inadmissible. This article challenges that conclusion in two ways. First, it argues that the rationale for accepting Williams’ original argument for the ‘realism constraint’ fails. Secondly, it argues that there is at least one genuinely political value of liberty available which is both compatible with realism and something that cannot be offered by the state, namely that of the political anarchist. This opens the way for far more ambitious and utopian forms of realist political thought and implies that the arguments of what we call political anarchists must be met by (realist) political argumentation, not simply ruled out by methodological stipulation. Accepted at the European Journal of Philosophy.