Foucauldian critical studies are cornucopian in illustrating how policy as discourse normalizes and yields human beings into made subjects in modern societies. However, Foucault's own slide from the 'terminal stage of discourse' pays little attention to the linguistic elements, and thus weakens the theory's potency in explaining the reality. Specifically, when the production of desirable subjects implicates clear target/norm-setting, ambiguous expressions are persistent in policy documents. To explicate this contradiction, this article firstly traces back to the foundation of Foucault's critical approach to policy analysis - socio-linguistic studies, to demonstrate the inevitable existence of ambiguity in language. It then continues such interdisciplinary efforts by combining research in public administration, politics and international relationship, to explore the positive effects of equivocalness in policy texts. Empirically based on China's regulation over transnational higher education, this study argues ambiguous expressions facilitate modern states, especially those fraught with conflicting discourses to mask the discursive conflict and leave negotiation room for innovative policy enactment. The vague norms of subject production are thus both inevitable and intentionally employed in policy developments.