Baker v. Carr was a U.S. Supreme Court case in 1962 in which it was decided that the Tennessee legislation had to reapportion itself based on population. Before that, the last time that Tennessee had redistricted was in 1901.
This case had a Republican plaintiff, Charles Baker, who asserted that since Tennessee was not redistricting every 10 years as the Tennessee State Constitution mandated, his Shelby County district had approximately 10 times as many residents as some of the more rural districts. Therefore, the votes of rural residents were more valuable than those of urban residents, such as Baker. The Supreme Court agreed that residency should not determine how much value a person's vote has.