In the case of Swann v. Adams, a group of voters from Florida challenged the constitutionality of their state's apportionment plan for both houses of its legislature. They argued that it violated the Equal Protection Clause in the Fourteenth Amendment because it did not ensure equal representation for all citizens due to population disparities among districts. The Supreme Court ruled in favor of Swann and his fellow plaintiffs, stating that Florida’s legislative apportionment scheme was indeed unconstitutional as it failed to achieve "fair and effective representation for all citizens." This ruling reinforced previous decisions by emphasizing that each citizen must have an equally effective voice in elections, thus reinforcing principles established during earlier reapportionment cases such as Baker v. Carr (1962) and Reynolds v. Sims (1964).

In the dissenting opinion for Swann v. Adams, it was argued that the court majority had overstepped its authority by intervening in a state's legislative apportionment process without clear constitutional or legal justification. The dissenters believed that there were no explicit standards in the Constitution regarding how states should draw their district lines and felt that this issue fell within a state's rights to self-governance under federalism principles. They also expressed concern about potential judicial activism, arguing that courts should not involve themselves in political matters unless absolutely necessary due to clear violations of individual rights or constitutional provisions. In essence, they disagreed with the majority’s decision on grounds of jurisdictional overreach and lack of concrete legal basis.