Leveraging quasi-experimental designs, this project tests whether personal networks effectively structure the political opportunity of individuals. We theorize that the propensity of individuals to run for and attain office is shaped by who they know—and that, in extension, representational inequalities visible in US electoral institutions is driven by the prevalence of informal networks. To test our theory, we web scrape biographical information of individuals that ran for state assemblies during the period of 1996 - 2016. To test our outcomes (political candidacy and success) we use a ‘close elections’ design, comparing the effects of knowing a close election winner, against the effect of being connected to a close election loser. We draw on new computational methods for the extraction and coding of our data set and extend on the efforts of previous scholars that have linked and harmonized administrative data from multiple jurisdictions and federal agencies.