Final answer:
Gideon v. Wainwright (1963), which expanded the right to counsel provided by the Sixth Amendment to state courts, represents a shift in the balance of power toward the federal government and was justified by the Due Process Clause of the Fourteenth Amendment.
Step-by-step explanation:
The case that represents a shift in the balance of power between the federal government and state governments, justified by a constitutional clause, is Gideon v. Wainwright (1963). The decision was justified by the Due Process Clause of the Fourteenth Amendment. This clause is a safeguard against the arbitrary denial of life, liberty, or property by the government outside the sanction of law. The Gideon case established the right to legal counsel for criminal defendants under the Sixth Amendment, which was applied to the states through the Due Process Clause of the Fourteenth Amendment. This significantly shifted power toward the federal government by ensuring that states also adhere to this aspect of the Bill of Rights.