The reforming tradition holding that social problems are neither natural nor permanent, that they yield to organised knowledge and public action, and that institutions therefore ought to be continuously revised rather than conserved. Its temperament is experimental: it treats government as an instrument for solving problems and expertise as the resource that makes solutions possible.
American Progressivism took shape between the 1890s and the 1920s as a response to industrial concentration, urban squalor and machine politics. Herbert Croly's The Promise of American Life (1909) supplied its intellectual charter, arguing that Jeffersonian ends now required Hamiltonian means — that a national state strong enough to match national corporations was the precondition of democratic equality. Theodore Roosevelt's New Nationalism and Woodrow Wilson's New Freedom offered rival versions. Jane Addams built the settlement house into an instrument of social knowledge, and John Dewey gave the movement its philosophy, treating democracy as a mode of shared inquiry rather than a set of procedures.
Its achievements were institutional and durable: antitrust, food and drug regulation, the income tax, direct election of senators, the secret ballot, professional civil service, and the beginnings of the administrative state. Its record also includes a great deal that its heirs disown. Progressive confidence in expertise extended to eugenics, immigration restriction on racial grounds, and — in Wilson's case — the resegregation of the federal civil service. This is not incidental to the movement's logic; the same faith that experts should manage social problems produced both the pure food law and the sterilisation statute.
The word has since shifted meaning, naming after the 1960s a broadly cultural liberalism rather than the administrative reform programme. The standing objection to both is the same one Dewey spent his career answering: that rule by expertise is in tension with rule by citizens, and that the tradition has never fully settled which it is committed to.