Social democrat political parties emerged during the late nineteenth century in a number of European countries including Germany, Sweden and other Scandinavian countries as well as in the Low Countries. Except in Germany, these broke with Marxism or had developed with very little meaningful Marxist influence to begin with. Some could trace their institutional and ideological roots to earlier utopian movements, cooperatives and trade unions. Some such parties were broad churches that contained Christian socialists as well as Marxist fringes. Some emphasised a nationalist case for social democracy as a means of promoting social cohesion. Their defining characteristic, a commitment to securing ongoing socialist reform through democratic means, mirrored that of Christian Democrats who differed from some earlier confessional parties by also being committed to parliamentary democracy. Political parties that called themselves social democrats often differed considerably beyond a shared rejection of an insurrectionary route to power. However, as remains often the case within democratic Left parties, different understandings of socialism and approaches to achieving change competed with one another.

In a 1925 lecture, Ernst Wigforss (1881–1977), a prominent member of Sweden's Social Democratic Worker Party, described his party's aspirations for socialism as working to achieve ‘a provisional utopia.’ He argued that socialists should not operate with fixed blueprints and that one's personal life and politics unfolded as a continuing series of experiments. A sensible person or political movement approached life not with dogmas but with working hypotheses. He argued that socialism must be empirical; it must be experimental; it must evaluate the success of its reforms against the tests of experience; it must allow for miscalculation and failure in its efforts to achieve reform. The impossibility of seeing all the consequences of new measures required a willingness to address unexpected consequences. A provisional utopia, as such, was a tentative sketch of a desirable future society that offered a guide to political action but would need to be revised in accordance with future experience. According to Wigforss, the value of setting out a provisional vision of the socialist future was threefold: it guided the work of social reconstruction by translating abstract values into concrete institutional recommendations; it facilitated rational political debate about how to make this work; and it served to inspire the work of social transformation by enlisting the moral energy of citizens.