Which U.S. Supreme Court case established the principle of "one person, one vote"?

The principle of "one person, one vote" was established by the Supreme Court case Baker v. Carr in 1962. This landmark decision addressed the issue of legislative representation and the way electoral districts were drawn. Prior to this case, many states had district maps that had not been updated to reflect population changes, resulting in a significant disparity in the weight of votes cast in different districts.

The Court ruled that legislative districts must be roughly equal in population to ensure that each citizen's vote carries the same weight in elections, thus upholding the principle of representative democracy. This decision reinforced the idea that voters in less populated districts should not have an outsized influence compared to those in more populated areas. This principle laid the groundwork for future cases regarding electoral fairness and representation in the United States.

In contrast, Roe v. Wade primarily dealt with reproductive rights, Brown v. Board of Education focused on racial segregation in public schools, and Worcester v. Georgia involved the rights of Native Americans and state authority, none of which relate to electoral representation or voting rights.