This dissertation empirically examines three pressing social justice issues in the United States. In the first chapter, titled "Black Lives Matter's Effect on Police Lethal Use-of-force," I explore the influence of Black Lives Matter protests on police lethal use-of-force. A difference-in-differences design finds census places with protests experienced a 15% to 20% decrease in police homicides from 2014 through 2019, around 300 fewer deaths. This decrease was prominent when protests were large or frequent. Potential mechanisms behind the reduction include police agencies obtaining body-worn cameras to curtail force and depolicing following a so-called `Ferguson Effect.' Fewer property crimes, but more murders, were reported to agencies with local protests, yet the property crime clearance rate fell. In the second chapter, titled "Beyond the Gender Binary: Transgender Labor Force Status in the United States 2014-2017," coauthored with Lee Badgett and Everest Brennan Lindesmith, we explore transgender labor market outcomes in the United States, building from social identity theory to provide a formal model of gender - the interplay between gender identity, expression, and perception. We apply this model using the Behavioral Risk Factors Surveillance Systems, finding evidence of labor market penalties associated with feminine identities, expressions, and perceptions. In the third chapter, titled "The Role of the Fragmented United States Healthcare System in Exacerbating COVID-19 Mortality," coauthored with Alison P. Galvani, Meagan C. Fitzpatrick, and Gerald Friedman, we associate health insurance coverage with COVID-19's mortality and contagion. Early in the pandemic, the US was disproportionately affected by COVID-19 with a mortality rate several times that of other affluent societies. By comparing state-specific demographic groups with different rates of health insurance, we assess how much of this excess mortality may be due to the relatively large population without health insurance. We also compare COVID-19 outcomes across contiguous county pairs that straddle state borders with different Medicaid eligibility poverty thresholds. Had there been full health insurance coverage of the population, there would have been 60,000 fewer deaths, 26% of the total deaths in our sample, according to our estimates. Our study demonstrates a significant share of COVID-19 mortality is due to reliance on market-driven healthcare.