Criminal Law

by John Bandler

Criminal law is one of many areas of law and arguably one of the most important.

Criminal prosecutions are where the government brings a case against a defendant on behalf of society, and the consequences for an individual can be severe, especially in comparison to other legal cases. Civil cases which are to address more individualized harms, and typically the consequences are merely monetary.

Criminal law is where the government exercises some of its most powerful domestic powers--the power to arrest an individual and take them into custody and bring them (forcibly if needed) before a court to answer charges. The power even to incarcerate an individual, to sentence them to jail and take away their freedom. And even in the rarest of circumstances to impose the death penalty.

Of course, there is good reason criminal law has these powers. In the world of people's criminal activity against others, civil process and civil remedies would be inadequate.

Criminal law has two main parts

Criminal law has two main parts:

  • Criminal procedure law
  • Substantive criminal law

Criminal procedure is a the process of administering criminal justice. For example, when can a police officer make an arrest, what happens after the arrest, the appearances in court, motion practice, hearings, trials, appeals, and all of that.

Criminal procedure also includes the complex area of evidence gathering, including protections of the Fourth Amendment, protections against unlawful searches and seizures by the government.

"Procedure" may seem like a tedious word, but criminal procedure is an important and fascinating area.

Substantive criminal law are the criminal statutes that define what a crime is. These statutes are enacted by a legislature. To be charged and ultimately convicted of a crime, there needs to be a statute defining that crime.

For example, New York defines the crime of Petit Larceny as "A person is guilty of petit larceny when he steals property." Then it has definitions of what the meaning of "steals" and "property" are.

Elements of a crime

A crime will almost always have these important elements:

  • Mens rea (Guilty mind)
  • Actus reus (Guilty act)
  • Other elements

Most crimes require a guilty mind, or a culpable mental state, such as intent, knowledge, recklessness, or criminal negligence. Mere accidents or common negligence rarely become the basis for criminal action (through they could be the basis of a civil suit).

Most crimes require a guilty act. The performance of some action. In rare circumstances a failure to act might suffice.

Other elements will usually be specified also.

Criminal law is enacted by different governmental units (sovereigns)

Criminal law is enacted by different governmental units, or sovereigns. These include:

  • The federal (U.S.) government
  • State government - 50 separate states each with their own criminal laws for procedure and substance
  • Territories and Districts (Puerto Rico, Guam, District of Columbia, etc.)

One criminal act could violate the laws of multiple sovereigns, and could result in multiple prosecutions, and would not usually violate double jeopardy provisions. For example:

  • A person shooting a gun from State X and hitting a victim in State Y is probably violating the laws of both states and the federal government
  • A cybercriminal committing a cybercrime from Country X into The USA, State Y is probably violating both federal and state laws

The authority of the government to prosecute, and the court to hear that case is a matter of jurisdiction.

Criminal laws are enforced by different governmental groups

Federal criminal laws are enforced in federal court, in front of a federal judge, with a federal prosecutor. Typically it is federal law enforcement involved with these investigations, but that does not have to be the case.

State criminal laws are enforced in the state court, in front of a state judge, with a state prosecutor. Typically, it is state or local law enforcement involved with these cases, but again that does not have to be so.

When watching the news, we mostly hear about federal cases, and hear from former federal prosecutors. And when the feds bring a case, they really make a federal case out of it. They typically put a lot of resources into it, and they are typically bigger cases.

Despite the attention afforded to federal criminal prosecutions, they are rare. Federal prosecutors and law enforcement have the luxury of declining to investigate or prosecute cases that do not reach their thresholds, and they bring only a tiny percentage of all criminal cases in this country.

State prosecutions make up the vast majority of all criminal prosecutions in this country. They may not be in the news as much, but that is where most criminal justice work happens.

The Fourth Amendment governs the process of collecting evidence

The highest law in the country regarding the collection of evidence by government is the Fourth Amendment of the U.S. Constitution. It is only 54 words, and millions more have been written to interpret what it means and how it applies to all sorts of circumstances.

States have their constitutions too, and there are federal and state laws regarding the collection of evidence.

The luxuries of being a criminal prosecutor

This header seems weird, right? I was a criminal prosecutor for 13 years, the pay was low, the workload was enormous, the work was challenging and difficult.

But there were some luxuries. The goal of a prosecutor is fairness and the interests of justice. Few other lawyers have this luxury, to represent a case that is meritorious, backed by facts and the interests of justice. Most lawyers need to zealously represent their clients (within the bounds of law and ethics) whether their client was right or wrong.

Of course, people will disagree on what is fair and just, and not every criminal prosecution is perfect. I am just commenting upon the overarching goal.

Criminal law and criminal enforcement is important and always will be

It seems obvious to me that there are some in society that will victimize others unless there are consequences. And that even with consequences, people do bad things.

We need criminal law, we need police to do the important and dangerous things that police do, and we need prosecutors.

There are some who seem to demonize the entire criminal justice system and all the people who work within it. There are some who state that society would be better off without criminal enforcement. But that is misguided and wrong.

We will always need a thoughtful and effective criminal justice system, with good people serving within it.

And we should have thoughtful and reasonable discussions about what we want our criminal justice system to do. Unfortunately there is rhetoric and extreme positions on both sides which detracts from these reasonable discussions.

Civil law comparedCriminal law vs Civil Law Bandler 2023-12

In contrast, civil law is essentially all of the other areas of law that are not criminal law. In civil law, a private individual or company can bring a lawsuit against another, typically for monetary damages.

While criminal law is immensely important for the people involved in it (victims, defendants, prosecutors, defense attorneys, judges, and all the other participants), civil law is much bigger and includes many discrete areas of law. More lawyers practice in civil law than criminal law. For more, see my article on civil law.


Criminal law is an important area of law. It is where government protects society and can take an individual's liberty away. We need to have thoughtful conversations about criminal law and the criminal justice system. We should not demonize police and prosecutors, nor pretend that society can work without an effective criminal justice system. We don't have to pretend criminal justice professionals and workers are perfect or make perfect decisions all the time, but let's apply facts and reason to the debate.

This short article has many simplifications, is not tailored to your circumstances and is not legal or consulting advice.

If you want to learn more about law, there is lots on this site, and my Udemy course.

If your organization needs help with improving its internal documentation and compliance with laws and regulations, including regarding cybersecurity and protecting from cybercrime, let me know.

Additional reading

This article is hosted at, copyright John Bandler, all rights reserved.

This article is also available on at NOT YET (though not kept as up to date).

Originally posted 8/16/2023, updated 12/14/2023.