The National Republican Senatorial Committee and other Republican Party committees challenged federal limits on expenditures that political parties coordinate with their candidates. The Sixth Circuit rejected the challenge because it was bound by the Supreme Court’s earlier decision in FEC v. Colorado Republican Federal Campaign Committee. The Supreme Court reversed, holding that the coordinated-party-expenditure limits violate the First Amendment. The limits burden core political speech and association by restricting how parties and candidates may work together to advance shared electoral messages, and the government did not justify that burden as a constitutionally permissible anticorruption measure. The Court therefore displaced the controlling effect of Colorado II and remanded for further proceedings.