 In the "Katzenbach v. Morgan" case, decided in 1966, the Supreme Court concluded that Congress can forbid practices that are not themselves unconstitutional, if the law is aimed at preventing or remedying constitutional violations.On that basis, the Court upheld a provision of the Voting Rights Act that prevented states from using English language literacy tests as qualifications for voting.The Court decided that the law was a valid exercise of Congress's enforcement power under the Equal Protections Clause of Fourteenth Amendment, because it was aimed at remedying state-sponsored discrimination, despite an earlier court finding that a literacy test was not in and of itself a violation of the 14th Amendment.