My dissertation examines how political institutions -- such as dual mandates, committee systems, and political associations -- impact the level and timing of party consolidation in a new democracy, as well as incentivize the behavior of elite politicians. I explore this through an intensive, data-driven analysis of the French Third Republic (1870-1940), during its formative years of its democratization. I trace the evolution of French political development across three papers. I first begin in the electorate, by looking at how a lack of ``bottom-up" electoral pressures slowed early political competition in France, and use an exogenous shock to population to demonstrate how urbanization affected local races and the creation of the first political associations in 1901. I then link the electorate with the legislature by examining how an institution meant to connect local and national politics -- cumul des mandats, or the ability to hold two offices -- had a negative effect on party development. Finally, I look at how the legislative organization of the committee system affected the career trajectories of politicians, in the absence of party institutions. In sum, this research contributes to a growing microfoundations literature that argues the geographic distribution of voters and the incentives of political elites are crucial but understudied factors in key episodes of early institution building in new democracies.