How does science-for-policy operate within authoritarian states in contrast to governments with the liberal-democratic ideals of the West? Authoritarian regimes often value scientific input—particularly in engineering, military, and economic development—but typically constrain the autonomy and openness that define scientific communities in democratic societies. The chapter focuses on the Soviet UnionSoviet Union” and the People’s Republic of ChinaChina” to show how science can flourish when aligned with state priorities, yet becomes vulnerable when ideological conformity, repression, or utilitarian objectives override epistemic norms. Case studies—including the politicisation of genetics under Stalin, environmental activism at Lake BaikalLake Baikal”, and China’s contested Nu RiverNu River” hydroelectric project—reveal how science must navigate power structures that limit public dissent and restrict access to decision-making. These examples highlight the mechanisms authoritarian governments use to filter, co-opt, or suppress scientific advice, while also illustrating how scientists, NGOs, and even artists can occasionally shape policy through indirect influence or strategic alignment with state goals. The chapter also reflects on the recent drift toward populismPopulism” in some democratic nations, noting similar tactics of restricting academic freedom, politicising expertise, and undermining institutional independence. As science becomes increasingly entangled with power with illiberalism and populism, understanding how it is mobilised—or marginalised—offers insight into both its potential and its limits in shaping public policy under constrained political conditions.