Speaking truth to power: nursing's legacy and moral imperative.

Critical caring has been proposed as a mid-range theory to guide public health nursing. One of its carative health promoting processes, contributing to the creation of supportive and sustainable physical, social, political, and economic environments, is particularly suited to enacting Nightingale's legacy of political action as an expression of caring. Increasing evidence supports the link between broad societal influences on health inequities. Relative and absolute poverty are significant influences on health and contribute significantly to differential health statuses of populations within and between countries. Nurses, who practice at the intersection of public policy and personal lives, are, therefore, ideally situated and morally obligated to include political advocacy and efforts to influence health public policy in their practice. The health of the public and the future of the profession may depend on it.