The Obama administration and state of Texas opposed the lawsuit. Civil rights groups watched the case carefully, fearful that if the court were to rule with the plaintiffs, it could potentially shift power from urban areas -- districts that tend to include a higher percentage of individuals not eligible to vote such as non-citizens, released felons and children -- to rural areas that are more likely to favor Republicans.
Civil rights groups feared that Latino communities in certain states with nonvoting residents, as well as children and others, would be sharply disadvantaged if the court were to side with Evenwel. "Drawing districts to equalize people is the only way to ensure that the communities where people live and work are fairly represented in the nation's legislatures," Michael Li, counsel for the Brennan Center's Democracy Program said after oral arguments.
Also supporting Texas was Nathaniel Persily of Stanford Law School, who said that if the court were to say that the Constitution requires states to use the voting population, it could unleash a series of questions regarding the reliability of voter lists and surveys. "A national database of eligible voters does not exist and will not exist in the foreseeable future," he said in an amicus brief.Keep in mind that the Constitutional basis of the census in the US is to count everyone so that Congressional districts can be drawn on the basis of population counts. When the country was founded, the fraction of people eligible to vote was actually pretty small, but that didn't matter in terms of drawing Congressional district boundaries. With today's Supreme Court decision, it appears that we will continue to follow the time-honored pattern of drawing both national and state legislative boundaries on the basis of total population numbers, not on the basis of some select group within the population.