Until it was overruled by Baker v. Carr in 1962, Colegrove v. Green (1946) was the leading precedent on legislative apportionment, holding that apportionment was a “political question” and therefore not within the power of courts to decide.
The case itself involved a challenge to Illinois’ congressional elections. According to the petitioner, the districts from which Illinois’ members of the U.S. House of Representatives were elected were so unequal in population as to violate the Constitution. Justice Felix Frankfurter, writing for the majority, refused to consider Colegrove’s contention, maintaining that “authority for dealing with such problems resides elsewhere. The Constitution [Article I, Section 4] has conferred upon Congress exclusive authority to secure fair representation by the States in the [House of Representatives].” “Courts,” according to Frankfurter, “ought not to enter this political thicket.”