Since the advent of the modern state, ruling classes have tried to restrain the voting power of workers and those not “wellborn.” Contrary to the mainstream story that capitalism naturally gave rise to democracy, establishment powers in nineteenth-century Europe restricted the vote for as long as they possibly could. Only when faced with mass mobilization — or when continent-wide war wiped out working-class males en masse — was it clear that the franchise could no longer be withheld.

The particulars of individual European countries varied. In some nations, following intense struggles, workers won limited forms of universal male suffrage before World War I. More commonly, broad suffrage rights appeared only after the war.

But what was consistent were the actors pushing for universal suffrage: trade unions and, crucially, socialist parties. In fact, what has been called the “democratic breakthrough” of the nineteenth century could easily be called the “socialist breakthrough.”