It began as an outcry against "the dark satanic mills" of early capitalism, a shuddering reaction against the profound upheavals caused by the Industrial Revolution, a reassertion of the Utopian dream of the heavenly kingdom on earth. It sprang from obscure clubs, from workers' associations, from garrets, libraries, bourgeois parlors and, occasionally, aristocratic salons. It was hounded, reviled, extolled. It became the most pervasive political ideology—or slogan—of the 20th century. Socialism.
Today it seems to have reached new heights of influence.
France nears the threshold of what Socialist Leader François Mitterrand calls "l'expérience socialiste"—and could cross it if...