Facebook is the most popular social networking platform in the United States, yet research into its impacts on political participation has been hampered by difficulty in obtaining user data. My work focuses on two approaches to measure the impact of political behavior on Facebook: digital trace data paired with surveys, and in-network experiments. In this talk I will present findings about how well individuals' self-reported political behavior on Facebook matches up with their actual activity on the platform, as well as their accuracy in estimating the partisanship of their networks. I will also present results of in-network experiments that explore the impact of Facebook posts on voter behavior and attitude change. I will also address some of the broader challenges of conducting research on Facebook in the current political and (un)regulatory environment.