In 1999, the Vermont Republican State Committee and other plaintiffs filed a federal district court constitutional challenge to various provisions of Vermont state campaign finance law, including the state’s contribution and expenditure limits. The U.S. Supreme Court granted cert on the questions of whether Vermont’s candidate expenditure limits contribution limits ranging from $200-$400 per candidate violate the First Amendment. The Court struck down both the expenditure limits and the contributions limits. With respect to the expenditure limits, the Court relied on its 1976 decision in Buckley v. Valeo striking down federal expenditure limits on First Amendment grounds. With respect to the contribution limits, the Court noted many differences between Vermont’s limits and the federal and state contribution limits the Court had upheld in earlier decisions against constitutional challenge. The Court found Vermont’s limits to be much lower and more restrictive than the constitutionally permissible contribution limits at the federal level and in other states. Although the Court invalidated Vermont’s contribution limits, the Court’s decision left in force federal limits and limits in other states.

Plaintiff Kean for Congress Committee brought suit against the FEC seeking judicial review of the agency’s dismissal of an administrative complaint. Kean Committee’s administrative complaint concerned political advertisements made against Thomas H. Kean, Jr., a candidate in 2000 for the New Jersey Seventh Congressional District.  The trial court refused to grant the FEC’s motion to dismiss and the FEC’s motion for summary judgement.  The case was eventually settled, and attorneys’ fees were awarded against the FEC.

In February 2005, ballot measure committee Citizens to Save California challenged a California Fair Political Practices Commission regulation establishing a presumption that all contributions to a candidate-controlled ballot measure committee are contributions to a candidate for elective state office subject to candidate contribution limits. The trial court granted plaintiffs’ motion for preliminary injunction. Defendant appealed and in December 2006 the Court of Appeal of the State of California, Third Appellate District, affirmed the trial court’s holding that the regulation conflicted with multiple provisions of the state’s Political Reform Act and thereby exceeded the FPPC’s authority; the court deemed it unnecessary to rule on the constitutional claims in the case.

In August 2000, California Pro-Life Council (CPLC) filed a constitutional challenge to California’s reporting and disclosure requirements applicable to groups advocating for or against state ballot measures. The district court dismissed the CPLC’s claims and upheld the challenged state law provisions, and CPLC appealed the decision. In November 2007, the Ninth Circuit Court of Appeals reversed the lower court in part, holding that “mixed purpose” organizations that only occasionally support or oppose ballot measures do not have to register as political committees and comply with statutory record-keeping and reporting requirements. However, the court found that such organizations could be required to report contributions exceeding $1,000 which were used for ballot measure advocacy.

In October 2002, Reps. Christopher Shays (R-CT) and Marty Meehan (D-MA) filed a lawsuit in the U.S. District Court for the District of Columbia against the FEC challenging 19 regulations adopted by the FEC to implement Bipartisan Campaign Reform Act of 2002 (BCRA). In September 2004, the District Court struck down 15 of the 19 contested regulations and ordered the FEC to rewrite the rules. The D.C. Circuit Court of Appeals affirmed the District Court decision.

Plaintiff, North Carolina Right to Life, Inc., (“NCRL”) brought this action in 1999 challenging the constitutionality of North Carolina’s definition “political committee," trigger for when a communication constituted electoral advocacy requiring disclosure and the contribution limit applicable to independent expenditure political committees.

In a 2-1 decision, the U.S. Court of Appeals for the Fourth Circuit found the challenged portions of North Carolina's law unconstitutional.

The CLC, together with other organizations, filed as amici curiae in support of North Carolina’s law in the district court and court of appeals.

In 2000, plaintiffs Christine Beaumont and North Carolina Right to Life (NCRL) challenged the constitutionality of a federal law prohibiting corporations and labor unions from making direct contributions to candidates, as the prohibition applied to a nonprofit corporation whose primary purpose was to engage in political advocacy. The United States Court of Appeals for the Fourth Circuit found for the plaintiffs, extending a narrow exception to the ban on the use of corporate or union treasury funds for electioneering expenditures so it also applied to contributions. The Supreme Court upheld the corporate contribution prohibition in 2003, stating in its 7-2 opinion that it could not hold for the plaintiffs “without recasting our understanding of the risks of harm posed by corporate political contributions, of the expressive significance of contributions, and of the consequent deference owed to legislative judgments on what to do about them.”

The lawsuits challenging the constitutionality of the Bipartisan Campaign Reform Act of 2002 - eleven suits brought by more than 80 plaintiffs - were consolidated as McConnell v. FEC. The defendants in the case were the U.S. Department of Justice and the Federal Election Commission; the Act's principal congressional sponsors - Senators McCain, Feingold, Snowe and Jeffords and Congressmen Meehan and Shays -were intervenor-defendants. The Legal Center 's attorneys were among the counsel to the congressional sponsors.

A three-judge trial panel of the U.S. District Court for the District of Columbia issued a mixed decision on the law's constitutionality on May 1, 2003.

The U.S. Supreme Court issued its decision on December 10, 2004, upholding all key aspects of the Reform Act.