What are “traditional” districting criteria? The meaning of that term is critical to curbing abusive districting practices, because adherence to traditional criteria grants districting plans a prima facie impression of constitutionality and serves as a strong defense to racial gerrymandering claims. Yet, the Supreme Court has never intelligibly defined “traditional” districting criteria or its representative qualities. Exploiting this silence, conflicted interests are attempting to define that term in service of their private interests at the expense of the public’s. For example, legislatures pushing redistricting plans that would advantage certain parties or incumbents claim that those districting goals are “traditional”—and therefore must be judicially protected—by relying on anecdotal examples of a state having used them. This Article proposes a definition of “traditional” districting criteria that would both reduce such abuse and adhere to a commonly understood meaning of that word: widely accepted as standard practice. Under this alternative, which we call the empirical definition, a criterion is “traditional” only if a majority of states require or allow it and fewer than a quarter prohibit it in state constitutions, statutes, or legislative guidelines. According to the empirical definition and our database of the fifty states’ redistricting laws, compactness, contiguity, equal population, and preserving county and city boundaries are traditional criteria. Among others, partisan advantage, incumbent protection, and preserving communities of interest are nontraditional. The empirical definition would not only curb abusive districting, but also reduce the influence of undesirable judicial activism upon redistricting by binding judges’ discretion to an objectively discernible definition of “traditional” criteria. In addition to practical gains, the empirical definition is also validated by constitutional theory. Responding to concerns of judicial legislation, we argue that the empirical definition merely defines a central element of redistricting law, which the Supreme Court has failed to define, according to the public will and the Court’s requirement of traditionality. The empirical definition also advances a constitutional principle that courts purport, but often fail, to follow: redistricting must not unduly discriminate against any candidate. In the status quo, courts would uphold discriminatory criteria such as incumbent protection if they are applied consistently to all electoral districts in a state. Moreover, the courts’ “consistent application” approach would contradict their own precedents by incorrectly deeming certain criteria to be nontraditional, such as the contiguity principle. The empirical definition would neither commit such self-contradiction nor condone abusive redistricting on condition that everyone suffer from it.