When the Supreme Court returns for its next term in October, among the cases it has agreed to hear is a challenge to a fundamental practice that has governed American elections for generations.
When public-policy makers talk about a state's population, they generally mean the number of human beings living in that state — as counted or estimated by the U.S. Census Bureau.
That applies to a host of political actions, including the apportionment of seats in Congress and the Electoral College votes that choose the president.
At the federal level, seats in Congress have been assigned to the states based on their total population, regardless of age or voting status. At the state level, lawmakers and others who draw election maps have generally drawn districts for various offices on that same basis.
In a landmark case decided by the U.S. Supreme Court in 1964 (Reynolds v. Sims), states were ordered to make such districts "as near equal in population as practicable." This was referred to as the one-man-one-vote decision, more recently referred to as one-person-one-vote. States were no longer allowed to apportion their state senates, for example, with a single senator to represent each county — regardless of population.
But the court in Sims did not specify a precise definition of the word population. In the half-century that has passed, the court has also passed on several other opportunities to do so. The prevailing interpretation has been that the population meant all the people. But critics have long maintained that the court might as well have meant eligible voters, as the power to vote and be equally represented was what was at stake. Conservative jurists have raised the question, at least for the sake of argument, and Supreme Court Associate Justice Clarence Thomas did so in an opinion as far back as 2001.
The current case is Evenwel v. Abbott and the lead plaintiffs are two residents of a state Senate district in Texas who say their equal rights to representation are diluted, because Texas equalized the districts in population terms — not in terms of eligible voters. So, they argue, the eligible voters in some districts are more powerful than in others, because it takes fewer of them to elect a state senator.
The discrepancy is particularly pronounced in Texas because the state has so many residents who are not citizens. These include many longtime legal residents and also more recent arrivals who may not be eligible to apply for citizenship.
Analysts have noted that dividing districts based on eligible voters only would tend to shift the balance of representative power to localities with fewer children and fewer immigrants. The state of Texas has opposed the lawsuit in filings with a lower federal court, which ruled in 2014 that the plaintiffs' challenge was a political issue that was not judicially reviewable.
The case was filed by the Project on Fair Representation and its president, Edward Blum. Blum is former resident of Houston but has lived in Washington, D.C., for more than a decade.
Among his other efforts that reached the U.S. Supreme Court are the Fisher v. University of Texas case, which limited affirmative action in public college admissions, and Shelby County v. Holder, which eliminated a key section of the Voting Rights Act of 1965. Shelby released certain states and localities from the "pre-clearance requirement" by which the federal Department of Justice had to approve any chances to laws or rules affecting elections.