Section 1.1: The Criminal Justice System

A banner reading "Criminal Justice: An Overview of the System" by Adam J. McKee

The United States has many different criminal justice systems. Each state has its own system, and the federal government has its own as well. In this section, we will explore how these systems are made up by looking at the main parts they all share.

Video Overview

Video Overviews of this material are available on YouTube:

Reading Time: 10 minutes

Usually, when we refer to the criminal justice system in an academic context, we are referring to the typical way things are done across the United States.  As we will learn, there are many variations in how things are done from place to place.  The criminal justice system is traditionally divided into three main parts: the Police, the Courts, and Corrections.

Although it may seem like there is no connection between these different parts, they are all linked by something called the rule of law. This means that everyone in the United States must follow the law, even those who make, interpret, and enforce it. The most powerful law in the United States is the Constitution. It provides Americans with certain freedoms that the government cannot take away.

If a state or federal law violates any of these freedoms, it will be considered invalid. The Supreme Court and other appellate courts are responsible for interpreting these laws and deciding exactly what rights people have in the United States. If a government official violates someone’s rights, that person can seek help from the legal system to make things right.

So, while the United States has many different criminal justice systems, they all share some common parts and are linked by the rule of law. This helps ensure that everyone in the country is treated fairly and has their rights protected.

In the United States, if a government employee violates a citizen’s rights, the citizen can sue them under a law called Section 1983, which is part of the United States Code. This is an important way for citizens to protect their rights.

Another important part of the criminal justice system is the exclusionary rule. This rule was created by the Supreme Court to stop police from doing things they shouldn’t. According to the rule, evidence obtained illegally (in a way that violates someone’s constitutional rights) cannot be used in court. This helps make sure that the justice system is fair and follows the law.


When people talk about “police,” they usually mean the people responsible for enforcing the law. Most of these people work for the city. Still, there are also other law enforcement officers who are not technically considered police, such as sheriff’s deputies and state and federal agents. It’s important to know that the police do more than just enforce the law. They help maintain order and provide many different services to the community they serve. The police also investigate crimes, collect evidence, and work with prosecutors to get convictions in court.

Police officers are often called the “gatekeepers” of the criminal justice system because they are the ones who start the process of bringing people into the system. When dealing with citizens and suspects, police officers have a lot of power to make decisions. They can choose to ignore a minor offense, give a warning, give a ticket, or arrest the person. The seriousness of the crime plays a big role in how the officer makes these decisions. For example, an officer would not ignore or give a ticket to someone committing a serious felony.  This type of decision-making authority is known as discretion

The duties of police officers can be very general, like those of a patrol officer, or very specialized, like those of a homicide detective. How specialized an officer is depends on the size of the agency they work for. Bigger police departments in urban areas tend to have more resources and more specialized officers. However, the patrol division is the “backbone” of policing and is always a generalist function. A successful patrol officer needs to be good at many different things.

🔍 Reflect

Considering the role of police officers as “gatekeepers” of the criminal justice system and their use of discretion, what are some potential benefits and challenges of giving officers such decision-making authority? How might these benefits and challenges impact the relationship between the police and the community they serve?


In the American legal system, when someone is accused of breaking the law, the court decides whether or not they actually did it. If they did, the court decides what punishment is appropriate within the limits of the law. Because the legal system is set up to be adversarial, there are two teams in every court case. In criminal cases, one team is the prosecutor, who represents the government and tries to prove that the defendant committed the crime. The prosecutor is like the offense in a sports game. 

The other team is the defense attorney, who tries to show that the defendant did not commit the crime or should not be held responsible for it for legal reasons. The defense attorney is like the defense in a sports game. The judge acts like a referee, making sure both sides follow the rules of the “game.” The jury watches the game and decides who wins at the end. It’s important to remember that all cases in the adult criminal justice system are adversarial in nature.

In the legal system, when there is a dispute about what happened in a case, a finder of fact is needed to decide what the truth is. (A finder of fact is typically a judge or a jury, and their role is to listen to the evidence presented by both sides and make a decision based on the facts of the case). In criminal cases, this is often done through a trial by jury. A trial by jury is a legal proceeding in which a group of ordinary citizens is selected to hear the evidence presented by both sides and decide who is right. The jury is responsible for determining the facts of the case and deciding whether the defendant is guilty or not guilty based on the evidence presented. This process is an important part of the legal system and helps to ensure that justice is served.

🔍 Reflect

Given the adversarial nature of the American legal system, what are the potential strengths and weaknesses of having a trial by jury decide the outcome of criminal cases? How might this system impact the fairness and accuracy of verdicts, and what alternative methods could be considered?


The term corrections refers to many activities within the criminal justice system, such as probation, parole, jail, prison, and other community-based punishments. However, it can be hard to define what “corrections” actually means because people have different ideas about the purpose and goals of incarceration. Is it to punish them or to try to help them change their behavior? Does society send people to prison as punishment or for punishment?  Despite this disagreement, most people can agree that correctional institutions should focus on making sure the public is safe.

When we talk about corrections, it often involves talking about jails. Jails are usually run by a county sheriff and hold different types of prisoners. Some of the inmates are people who have been arrested and are waiting to go to court. These people are considered innocent because they haven’t been proven guilty yet.  In the United States, every suspect is considered “innocent until proven guilty” by the law. Other inmates are serving short sentences (less than a year) for minor offenses (called misdemeanors) in most states. Some prisoners in jails have been convicted of serious crimes and are waiting to be transferred to a state prison.

If someone is found guilty of a serious crime, they might be sent to prison. Prisons are different from jails because they are bigger, more secure, and offer more services. The reason for this is that prisons are meant for people serving long sentences, compared to the shorter sentences served in jails. State governments usually run prisons, but there are also federal prisons.

🔍 Reflect

Considering the different purposes and goals of incarceration, such as punishment and rehabilitation, what are the potential benefits and drawbacks of each approach? How do these perspectives impact the operations and effectiveness of correctional institutions in ensuring public safety?

Defining Justice

The criminal justice system has the goal of promoting justice, but it can be difficult to define what justice means. One way to look at justice is in terms of equality, where everyone is treated the same regardless of their circumstances. Another way to view justice is in terms of equity, where people get what they deserve based on their actions. When it comes to criminal justice, some people believe in retributive justice, which means that the punishment should fit the crime. This idea is based on the concept of lex talionis, or the law of retribution, which means that wrongdoers should receive the same harm they caused to others. In today’s criminal justice system, retribution often means that the length of a prison sentence varies based on the severity of the crime committed.

The concept of justice can be viewed in different ways, and one way is to examine the process of how a decision was reached. Procedural justice holds that an act is just if it was done using a fair process. However, what constitutes a fair process can be debated, with accessibility and predictability being common criteria. In the United States, procedural justice is closely tied to the idea of due process. Due process means that agents of the criminal justice system must conduct criminal proceedings in a fundamentally fair way. This means that the state must respect all legal rights of accused persons, which is a dynamic body of rules that courts often interpret. Due process is represented throughout the Bill of Rights, including the Fifth Amendment (for the federal government) and the Fourteenth Amendment (for state governments). The criminal justice system must adhere to these legal requirements, including police, courts, and corrections. Throughout this text, we will discuss how these fundamental civil liberties apply to different aspects of the criminal justice system.

It’s important to note that the Fifth Amendment in the US Constitution is constructed as a very long sentence that covers many different topics. This type of sentence structure is common in the Constitution. When lawyers and legal scholars want to draw attention to a specific phrase within this long sentence, they call it a “clause.” The due process clause is a part of the Fifth Amendment that specifies that “no person can be deprived of life, liberty, or property without due process of law.” 

While some fundamental liberties are expressed in the Constitution through clauses like this, other rights are not specifically stated. The due process clause is especially important for civil liberties because it stands in for many other rights that may not be stated explicitly. For instance, the right to privacy is not explicitly mentioned in the Constitution. Still, the Supreme Court has ruled that it exists as a necessary component of fundamental fairness in the criminal justice system.

🔍 Reflect

How do the different views of justice (equality, equity, retributive justice, and procedural justice) shape the way the criminal justice system operates?


The criminal justice system in the United States is made up of many different parts, including police, courts, and corrections. Despite their differences, all these parts are linked by the rule of law, which means that everyone in the country must follow the law, including those who make, interpret, and enforce it. The Constitution is the most powerful law in the United States, and it provides citizens with certain freedoms that the government cannot take away.

When there is a dispute about what happened in a case, a finder of fact is needed to decide what the truth is. This process is usually done through a trial by jury, which is an important part of the legal system that helps to ensure justice is served. Defining justice can be difficult, but different perspectives include equality, equity, and retributive justice. The concept of procedural justice also holds that an act is just if it was done using a fair process.

Due process is a fundamental part of the criminal justice system, and it means that agents of the system must conduct criminal proceedings in a fundamentally fair way. The Fifth Amendment to the US Constitution includes the due process clause, which is an important part of protecting civil liberties. Other important rights, such as the right to privacy, are not explicitly stated in the Constitution, but they are protected through the due process clause.

Overall, the criminal justice system in the United States is designed to promote justice and ensure that everyone is treated fairly and has their rights protected. The different parts of the system work together to investigate crimes, prosecute offenders, and provide punishment or rehabilitation. By understanding how the system works, citizens can better protect their rights and contribute to a fair and just society.

Key Terms

Adversarial (legal system), Bench Trial, Bill of Rights, Civil Liberties, Corrections, Courts, Crime, Criminal Justice System, Defendant, Defense Attorney, Discretion, Due Process, Due Process Clause, Equality (in Justice), Equity (in Justice), Exclusionary Rule, Fifth Amendment, Finder of Fact, Fourteenth Amendment, Incarceration, Individual Rights, Jail, Judge, Jury, Just Deserts, Justice, Lex Talionis, Parole, Police, Prison, Probation, Procedural Justice, Prosecutor, Retributive Justice, Rule of Law, Sheriff, Sheriff’s Deputies, Statute, Trial by Jury, United States Code

[ Back |  Contents | Next]

Last Modified: 05/16/2024
Cite This Page (APA)

McKee, A. (2024). The criminal justice system. In Criminal justice: An overview of the system (Section 1.1). Retrieved July 18, 2024, from

Print for Personal Use

You are welcome to print a copy of pages from this Open Educational Resource (OER) book for your personal use. Please note that mass distribution, commercial use, or the creation of altered versions of the content for distribution are strictly prohibited. This permission is intended to support your individual learning needs while maintaining the integrity of the material.

Print This Text Section Print This Text Section

15 thoughts on “Section 1.1: The Criminal Justice System

  1. This article was very helpful in articulating my post for my class, thank you for helping me to organize my thoughts on this subject.

  2. I learned a lot of great information in this reading. It really helps me understand about the laws and rights.

  3. There was quite a bit of information that I did not know about. Such as section 1983, I didn’t know that you could sue Government employees.

  4. The article was very helpful to me by how it broke down the criminal justice system as not just being one system.

  5. Reading this article made me learn somethings I wasn’t really aware of such as real meanings of certain laws and also how we can all interpret laws differently but this helped me to understand the real meaning of the law and how its works.

  6. This article was very informative to me as I didn’t know about the many components that make up our criminal justice system.

  7. I found this article to be highly engaging it provided me with a plethora of new knowledge, i loved it.

  8. Learning that each state has their own system this reading has taught me that it’s all still very similar snd come from the same branch just like police officers and sheriff’s.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.