Criminology Adversarial System of Justice
Rodger Benefiel
  • LAST REVIEWED: 26 May 2022
  • LAST MODIFIED: 26 May 2022
  • DOI: 10.1093/obo/9780195396607-0320


The legal framework of the United States is commonly referred to as an adversarial system. Based on English common law, it established normative procedures that mediate conflicts between opposing parties, with a goal of minimizing the impact of governmental actions on entrenched personal rights. In an adversarial system, the aggrieved party alleges there has been an injury, and is seeking relief from the defendant. In the American version of this system, the advocates for the involved parties will make their arguments before an impartial third party, which can be a judge or a jury. In either case, the judge is responsible for ensuring that defendants are entitled to their day in court, that their established rights are not violated (which provides a check against the power of the government), and that the case will be assessed on its merit, based on the arguments presented and how the law applies. However, critics of the system have proffered that the system is fraught with inconsistencies and biases, and believe it fails in its core mission of uncovering the truth. This has led some to advocate for a system based on a generalized ideal of an inquisitorial system.

Development of an Adversarial System

While the American adversarial system is rooted in English common law, its development was influenced by differing colonial needs (Nelson 2008–2018). Common law has a deep developmental history. One of the earliest documents significant for the evolution of the common law is the 1166 Assize of Clarendon, which helped establish the concept of petit juries. Another formative document is the Magna Charta, which influenced the adoption of individual liberties to serve as a protection against an oppressive ruler. English common law developed over time and did so through a combination of court decisions and established procedures. One major development for criminal law was the idea that the government (i.e., the monarchy) would take the place of the victim and allege injury when a citizen broke the law. According to Bodenhamer 1992, because the American colonists did not have much legal expertise, they combined what they knew of common law with common sense. This is disputed by Nelson 2008–2018, which showed that the common law was known but adherence was secondary to a colony’s particularized needs. The Massachusetts Body of Liberties of 1641, for example, combines elements of common law with religious law. After 1660, when England extended its control, the colonists eventually found English rule an intolerable breach of their inalienable rights. These feelings led to pronouncements of their duty to secede from despotic rulers (Virginia Declaration of Rights of 1776). After the revolution, the Constitution of the United States, including the Bill of Rights, included provisions for fair trials, right to counsel, and amendments that accentuated the desire for individual protection against the power of the state. Many of the Constitution’s formative concepts were influenced by Blackstone’s Commentaries, which brought common law and statutory law together. Because the new country found convincing a loose confederation of states to accept a national charter difficult, so Andrew Hamilton, James Madison, and John Jay produced eighty-five essays supporting the Constitution. Essays 78 through 83 specifically deal with the judiciary and its place in government. Through its many influences, the American adversarial system is now a complex web of legislation and court decisions. Fortunately, there are sources that provide concise explanations for many of the key concepts, such as West’s Encyclopedia of American Law.

  • Assize of Clarendon.

    The Assize of Clarendon is believed to have led to the establishment of juries. An assize court is a periodic court, commonly used in medieval England. The number twelve is associated with perfection/authority and is frequently referenced in the Bible; for example, Christ had twelve disciples, there were twelve minor prophets in the Old Testament, and Jacob had twelve sons that eventually formed the twelve tribes of Israel.

  • Blackstone’s Commentaries.

    Originally published between 1765 and 1769, William Blackstone’s efforts at bringing common law and statute law into one overarching theory of law is a cornerstone of the United States’ adversarial system. Blackstone’s views on natural law as God-given and providing people with free will and the absolute right of life, liberty, and property are foundational for the formation of the US Constitution.

  • Bodenhamer, David J. 1992. Fair trial: Rights of the accused in American history. New York: Oxford Univ. Press.

    This book discusses the development of the Constitution and how individual liberties were drawn from English common law and adapted to colonial circumstances. Bodenhamer traces how the Bill of Rights was formed, the evolving definition of due process, the continued struggle between federal and state jurisdictions, and contemporary issues regarding the application of individual rights under a changing perspective of substantive due process, with a focus on the interplay between the courts, the 14th Amendment, and the Bill of Rights.

  • Constitution of the United States.

    This is a link to, which provides a transcript of the US Constitution. This site also has links to each article and section as well as links to the Bill of Rights and the Declaration of Independence.

  • Hamilton, Alexander, James Madison, and John Jay. The Federalist Papers.

    The Federalist Papers were a series of eighty-five essays written by Alexander Hamilton, James Madison, and John Jay to help promote the ratification of the US Constitution. Essays 78 through 83 deal with the judiciary as a response to criticisms leveled against Article III of the US Constitution. Hamilton notes the judiciary will not have the power of the other branches of government, so it should be an intermediary between the legislature and the people to keep the legislature within its authority through independent interpretation of the law.

  • Magna Charta.

    This document, drawn up by the Archbishop of Canterbury and signed by King John I of England in 1215, contains provisions to protect barons from illegal imprisonment and limits payments made to the crown. The meaning of the Magna Charta has evolved over time to symbolize individual liberty and protections against an oppressive ruler. The website contains the text of the document as well as several videos and commentaries on its historical and contemporary significance.

  • Massachusetts Body of Liberties.

    The Massachusetts Body of Liberties is a 1641 document that amounts to a blend of Puritan theology and common-law principles, with an emphasis on individual liberties in an emulation of the Magna Charta. The principles contained in the Massachusetts Body of Liberties are an early version of individual rights and liberties contained in the Bill of Rights.

  • Nelson, William E. 2008–2018. The common law in colonial America. 4 vols. New York: Oxford Univ. Press.

    DOI: 10.1093/acprof:oso/9780195327281.001.0001

    This four-volume set traces the development and use of common law in the American colonies from the formation of the first settlements through the Declaration of Independence. Nelson argues that colonial law was grounded in the common law, but its use was secondary to social forces in the colonies, such as the need for free-market capital in Virginia and the convergence with religious law in Massachusetts. Eventually, the colonies came together in a sort of nascent federalism but retained elements of the earlier influences.

  • Virginia Convention Declaration of Rights.

    On 15 May 1776, the Virginia Convention called for a committee to draft a statement of rights in support of a resolution seeking independence from England. The document was primarily written by George Mason (James Madison wrote the section on freedom of religion) and was approved on 12 June 1776. The document contains sixteen sections and blends elements of the Magna Charta and English common law with colonial expectations. It is considered a precursor to the Bill of Rights.

  • West’s Encyclopedia of American Law.

    This is an online version of West’s Encyclopedia of American Law through, which requires a login but is free of charge. The encyclopedia is a resource for legal terms, cases, statutes, and issues. Some landmark cases are also included, as are selected historical documents. You are able to digitally borrow a volume for up to fourteen days.

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