I offer a novel way of documenting the flow of power between the state and federal governments. Rather than look at programs or expenditures, I examine the behavior of elected officials. Assuming that ambitious politicians gravitate toward the locus of political power, I track the flow of elected officials in the American federal system. Specifically, I look at the career paths of more than 12,000 individuals who served in the U.S. Congress between 1789 and 2012. By analyzing the movement of elected officials between the state and federal levels, I confirm the prevailing story line on the evolution of American federalism while generating a measure that can be used to assess the relative distribution of power in the system across time.