The law of criminal procedure consists of the rules the government must abide by to detect and
investigate crime, prosecute and convict defendants, and punish convicted offenders. The final
authority of criminal procedure lies in the U.S. Constitution, especially in the Bill of Rights. Most of the
criminal procedure provisions are found in the Fourth, Fifth, Sixth, Eighth and Fourteenth
Amendments. The Constitution and these rights are supreme, making the Constitution the final word in
matters involving criminal procedure. According to the principle of judicial review, courts are tasked
Article VI of the U.S. Constitution commands that the government follow its guidelines.
Although this sounds easy enough, the Constitution and its Amendments are vague and
ambiguous making it difficult to determine its meaning. Through the Supremacy Clause and the
principle of judicial rule the Supreme Court has determined that all criminal procedures are
accountable to the Constitution and any court can interpret it but the Supreme Court has the final
Every state constitution guarantees its citizens parallel criminal procedure rights, like the right
against self-incrimination, and against unreasonable searches and seizures. State courts are a
source of criminal procedure law in two types of cases: (1) those involving the U.S. Constitution
that the U.S. Supreme Court has not decided yet and (2) those involving their own state
constitutions. State courts are the final authority in cases based on their own state constitutions
and statutes. State criminal procedure rights might be broader than federal rights, but they can
not fall below the federal minimum standard defined by the U.S. Supreme Court.
From the adoption of the Bill of Rights until the 1960s, the rights afforded to criminal defendants
applied only in the federal criminal justice system. The U.S. Supreme Court, in a series of
decisions in the 1960s called the “due process revolution,” expanded the meaning of these rights
within the federal system and ruled that most of these expanded rights also applied in state and
local criminal justice matters. The Supreme Court relied on two Civil War Amendment
guarantees to accomplish its revolution: the due process and equal protection clauses of the
Fourteenth Amendment. After a decades-long struggle within the Court, a majority came to
The Court also came to agree that the ideal of equality is deeply embedded in our history, and
that since the Civil War, the Constitution commands equal protection of the laws. Equal
protection of the law does not require state officials to treat everybody exactly alike. It means