The present article reconstructs and analyzes in detail the path that the Chilean Democratic Party (PD) took during the final years of the nineteenth century, upon entering the Liberal Alliance and fully participating in the parliamentary system. The article argues that the PD had two basic motivations which were closely interwoven and which made its incorporation into the Liberal Alliance as well as its participation in the parliamentary political game inevitable. One of these motivations was ideological: the parties' anticonservatism and anticlericalism. The other was practical: the necessity to "defend" their congressional seats, which forced them to find allies in the process of certifying the elections by the parliament. At the same time both motives came from the reformist character of the PD, its' self-identification as the plebian side of liberalism (more resolute and consequent) and from its project to democratically reform the oligarchic state.