In The National System of Political Economy, List provides a critique of the ideas of Adam Smith and David Ricardo that continues to resonate with policy makers concerned with industrial policy and national economic development. List argues that in contrast with the stylized view of classical economics, real-world economies are organized along national lines and that policy makers can ignore this reality to their peril. The benefits from trade are conditional, rather than universal and the development of sophisticated industry requires carefully designed and sequentially planned state interventions. List provides an early recognition of the existence of distinct stages of economic development, and of the interplay between military power, industrial development and national prosperity. List's work had a formative influence on subsequent strands of thought such as institutional economics and 'national systems of innovation' perspectives and is considered an exemplar of work in the tradition of realist international political economy.