Abstract: Racial bloc voting is the central concept in judicial regulation of redistricting. For the past several decades, the definition and proof of this concept have depended on two premises: that polities can be conceptualized in biracial terms and that nearly perfect information on voting patterns can be inexpensively obtained from simple statistical methods. In fact, however, neither premise has been true for some time, as the nation has become multiracial and allegations have increased that Caucasians vote less monolithically than before, with both assertions imposing severe stress on the simple statistical methods previously used to assess voting patterns. In this article, I analyze these challenges to traditional understandings and attempt to answer the following question: how can we litigate racial bloc voting well in the current era? I provide recommendations, including greater reliance on more sophisticated statistical methods, an increase in the use of sample surveys, and a renewed receptivity to nonquantitative evidence on voting patterns, while clarifying that each of these recommendations carries substantial costs. I then discuss the conceptual and normative implications of my recommendations on the empirics.