This Article claims that takings law can accommodate the ideals of social responsibility and of equality, but argues against the conventional wisdom that restricting the regulatory takings doctrine as much as possible promotes this agenda. A uniform restrictive takings doctrine -- which is meant to enable democratic institutions to upset the status quo -- is counter productive from a progressive point of view, since it may yield a systematic exploitation of small and relatively less well-off landowners. Hence, a progressive takings doctrine must employ a much more refined criterion for distinguishing a regulation from a taking. This Article proposes such a criterion by reconceptualizing two familiar tests in takings jurisprudence: reciprocity of advantage, and diminution of value. It demonstrates that considerations of efficiency and personality support a distributive criterion designed to promote social responsibility and solidarity and to avoid structural privileges favoring the better-off. It also contends that this progressive criterion does not unduly hinder the concerns of liberty and of equity among the better-off. Finally, the Article shows that rather than being a radical transformation of the current law, the proposed theory provides a doctrinal vocabulary and normative underpinnings for a significant segment of extant takings jurisprudence.