Political economy treats production, politics and social structure as one subject. It takes seriously the political consequences of how an economy is organized, and judges economic arrangements in moral terms as well as by efficiency. It was the original name of the subject now called economics, and the change of name marked a narrowing.
The physiocrats around François Quesnay were its first systematic school. His Tableau Économique of 1758 modeled an economy as a circular flow of payments that reproduces itself annually, the earliest attempt to treat a nation's economy as a system instead of a ledger. Their doctrine that only agriculture yields a net product was wrong; their conclusions outlived it. Remove internal tolls and restrictions on trade, tax the net product of land, and let exchange operate. Smith met them in Paris in 1766 and called their system, with all its imperfections, the nearest approximation to the truth yet published.
The classical phase runs from Smith's Wealth of Nations (1776) through Ricardo and James Mill to John Stuart Mill's Principles (1848), the standard text for a generation. These writers took the wealth of nations as their subject, not the choices of individuals, and treated rent, class and distribution as inseparable from law and government. Marx then turned the discipline against itself, recasting it as a critique of capitalism's categories instead of an explanation of them.
The marginal revolution of the 1870s split the subject. Economics became the study of optimization under constraint and handed the political questions to other departments. Political economy survived at the margins, in the Austrian school, in Marxian scholarship, in institutional economics, before reviving from several directions late in the twentieth century.
The revival is broad enough that the term now covers incompatible projects. A public choice economist and a Marxian political economist both claim it while disagreeing about nearly everything, including whether the discipline exists to explain the existing order or to indict it.
