McConnell v. FEC is a 2003 United States Supreme Court case upholding the constitutionality of most of the Bipartisan Campaign Reform Act (better known as McCain-Feingold).

The case was brought by groups such as the California State Democratic Party and the National Rifle Association, and individuals including Senator Mitch McConnell (Kentucky), the (Republican) Senate Majority Whip, who argued that the legislation was an unconstitutional infringement on their First Amendment rights.

In June 2003, the D.C. Court of Appeals issued a ruling on whether the law was constitutional. That ruling never took effect, as the case was immediately appealed to the Supreme Court.

The Supreme Court heard oral arguments in a special session in September 2003. On Wednesday, December 10, 2003, it issued a complicated decision, totaling 300 pages in length, that with a 5-4 majority upheld the key provisions of McCain-Feingold.

Justice Breyer, Stevens, O'Connor, Souter, and Ginsburg established the majority for two parts of the Court's opinon:

• With respect to Titles I and II of the BCRA, Justices Stevens, O'Connor wrote the opinion of the Court.
• With respect to Title V of the BCRA, Justice Breyer wrote the Court's opinion.

A different 5-4 majority established the Court's opinion on the rest of the act:

• With respect to Titles III and IV of the BCRA, four justices (O'Connor, Scalia, Kennedy, and Souter) joined Chief Justice Rehnquist, who wrote the opinion of the Court. The four remaining justices also joined most of the opinion.

Two dissenting opinions were included in the decision:

• Justice Stevens, joined by Justices Ginsburg, and Breyer, dissented on one section of the part of the Court's opinion written by the Chief Justice.
• The Chief Justice, joined by Justice Kennedy and Scalia, issued a 15-page dissent against the Court's opinion with respect to Titles I and V of the BCRA.

Three other justices wrote separate opinions on the decision:

• Justice Kennedy, joined by the Chief Justice, issued a 68-page opinion and appendix, noting that BCRA forces "speakers to abandon their own preference for speaking through parties and organizations."
• Justice Thomas issued a separate 25-page opinion noting that the Court was upholding the "most significant abridgment of the freedoms of speech and association since the Civil War."
• Justice Scalia issued a separate 19-page opinion, a "few words of [his] own," because of the "extraordinary importance" of the cases.