Sustainability has become a major goal of domestic and international development. This essay analyzes the transitions of normative ideas embedded in the notion of sustainability by reviewing the discourses in the representative reports and literature from different periods. Three sets of ideas are proposed: inter- and intra-generational equity, stability of public systems, and a sense of solidarity, which confirms the scope of community and functions as a precondition for the previous two ideas. This essay uses the case of a health (...) system in a hypothetical country to illustrate that, besides securing financial sustainability, a genuinely sustainable public system must also meet the three normative ideas of sustainability. This essay also finds that these three ideas may create intrinsic tensions within the prevalent policy-making model—democracy. The pursuit of sustainability is not only the responsibility of a democratic government, but also a shared moral obligation of the body politic. (shrink)