What Is Criminal Law? Criminal law is the area of law that defines conduct considered harmful or unlawful by the government and establishes the penalties and legal procedures that may apply when someone is accused of committing a crime. In the United States, criminal law operates at both the state and federal levels, which means the specific offense, applicable law, court, and potential penalties can depend on where the alleged conduct occurred and which government has jurisdiction.
Unlike civil law, which generally deals with disputes between individuals, businesses, or organizations, criminal law involves the government prosecuting a person or entity for an alleged offense.
Understanding the basic principles of criminal law can help people better understand criminal charges, court proceedings, possible penalties, and the rights of an accused person.
What Does Criminal Law Mean?
Criminal law establishes rules identifying certain acts or omissions as crimes. It also establishes the potential consequences for violating those rules.
Examples of conduct that can constitute crimes include:
- Theft and certain forms of property offenses.
- Assault and other violent offenses.
- Drug offenses.
- Fraud.
- Burglary.
- Robbery.
- Certain weapons offenses.
- Sexual offenses.
- Homicide.
- Certain computer and cyber-related offenses.
- Certain offenses involving government property or federal interests.
The precise definition of a crime depends on the applicable statute and jurisdiction.
For example, an offense that is a crime under the law of one state may have a different definition, classification, or penalty in another state. Federal criminal statutes apply to offenses within federal jurisdiction.
The Legal Information Institute explains that a crime generally requires the prosecution to establish the elements defined by the applicable law. These elements can include the defendant’s conduct, required mental state, and the required connection between the conduct and the prohibited result.
How Is Criminal Law Different From Civil Law?
Criminal and civil cases can sometimes involve similar underlying events, but they serve different legal purposes.
Criminal cases
A criminal case is brought by the government against a defendant accused of violating a criminal law.
Depending on the jurisdiction and offense, the government may seek penalties such as:
- Imprisonment.
- Probation.
- Fines.
- Restitution.
- Other penalties authorized by law.
Civil cases
Civil cases generally involve disputes between individuals, businesses, organizations, or government entities. The potential remedies can include monetary damages, injunctions, or other forms of civil relief.
One event can sometimes result in both criminal and civil proceedings. For example, conduct involving alleged fraud could potentially lead to a criminal prosecution as well as a separate civil action.
What Are the Main Elements of a Crime?
A prosecutor generally must prove the legally required elements of the offense charged.
Two important concepts often encountered in criminal law are actus reus and mens rea.
Actus Reus
Actus reus refers broadly to the criminal act or conduct required by the particular offense.
The prosecution must establish the conduct specified by the applicable criminal statute.
Mens Rea
Mens rea refers to the required mental state associated with an offense.
Not every crime requires the same mental state. Depending on the statute, an offense may require proof of intent, knowledge, recklessness, or another specified state of mind.
Causation
For offenses involving a prohibited result, the prosecution may also have to establish the required causal connection between the defendant’s conduct and that result.
These requirements vary by offense. The elements of a particular crime are determined by the applicable law, and the government generally must prove the required elements beyond a reasonable doubt in a criminal prosecution.
What Is the Difference Between a Felony and a Misdemeanor?
Criminal offenses are commonly classified as felonies or misdemeanors, although the exact classifications and penalties depend on the jurisdiction.
Felonies
Felonies are generally more serious offenses and can carry significant prison sentences.
Examples can include certain:
- Homicide offenses.
- Robbery offenses.
- Serious drug crimes.
- Sexual offenses.
- Fraud offenses.
- Weapons offenses.
Misdemeanors
Misdemeanors are generally less serious than felonies and may carry shorter periods of incarceration, fines, probation, or other penalties.
However, a misdemeanor conviction can still have significant consequences for a person’s employment, professional licensing, housing, immigration status, reputation, and other aspects of life.
Federal law and state law can classify and punish offenses differently, so the classification of a particular offense should always be checked under the applicable jurisdiction.
What Is Criminal Law at the State and Federal Levels?
The United States does not have a single criminal code that governs every criminal offense nationwide.
Instead, criminal laws exist at both the state and federal levels.
State Criminal Law
States enact and enforce their own criminal statutes. State prosecutors generally handle cases involving violations of state criminal law.
Most traditional criminal offenses are primarily handled at the state level.
Federal Criminal Law
Congress creates federal criminal statutes, and federal prosecutors can bring cases involving offenses that fall within federal jurisdiction.
The U.S. Department of Justice explains that federal criminal cases arise from federal law, while state and local prosecutors generally handle cases arising under state law. Some conduct can violate both state and federal law, creating potential overlap.
Federal courts are courts of limited jurisdiction. Federal criminal cases must therefore fall within a basis for federal jurisdiction established by the Constitution or federal law.
What Types of Crimes Can Be Federal Offenses?
Federal criminal law covers a broad range of conduct.
According to the U.S. Department of Justice, examples include certain offenses involving:
- Narcotics.
- Bank robbery.
- Wire fraud.
- Mail fraud.
- Tax fraud.
- Firearms.
- Environmental violations.
- Civil rights violations.
- Fraud involving the United States.
Some offenses can violate both federal and state law. In those situations, prosecutors determine which jurisdiction will pursue the case based on the circumstances and applicable law.
Federal jurisdiction can arise from particular connections to federal interests, interstate commerce, federal property, federal programs, or other circumstances established by law.
How Does a Criminal Case Begin?
A criminal case can begin in different ways depending on the jurisdiction and circumstances.
In the federal system, an investigation may involve federal law enforcement agencies. A prosecutor may then determine whether there is a legal basis to bring charges.
The federal criminal process can involve several stages, including:
- Investigation.
- Arrest or summons.
- Initial appearance.
- Detention or pretrial release decision.
- Charging or indictment.
- Arraignment.
- Pretrial motions.
- Plea negotiations or trial.
- Sentencing following conviction.
- Appeal, when applicable.
Not every case follows exactly the same path.
The U.S. Department of Justice notes that federal criminal cases and state criminal cases can follow different procedures, and federal felony cases generally use grand-jury indictments unless the defendant waives that requirement.
What Is the Burden of Proof in a Criminal Case?
One of the most important principles in criminal law is the government’s burden of proof.
In a criminal trial, the prosecution generally must prove the defendant’s guilt beyond a reasonable doubt.
This is a higher standard than the preponderance of the evidence standard commonly used in many civil cases.
The defendant does not generally have to prove innocence. Instead, the government carries the burden of proving the charged offense and its required elements.
Federal courts explain that a defendant is presumed innocent unless and until the government proves guilt beyond a reasonable doubt.
What Happens If Someone Is Charged With a Crime?
Being charged with a crime does not mean the person has been convicted.
A criminal charge is an allegation that the defendant committed an offense. The case must proceed through the applicable legal process before a conviction can occur.
Depending on the circumstances, a defendant may:
- Plead guilty.
- Plead not guilty.
- Negotiate a plea agreement.
- Proceed to trial.
- Challenge evidence or legal issues through pretrial motions.
- Appeal a qualifying conviction or ruling.
A defendant’s rights and available legal strategies depend on the jurisdiction, charges, facts, and procedural stage of the case.
What Is Criminal Law Designed to Accomplish?
Criminal law serves several functions within the legal system.
Protecting the public
Criminal statutes prohibit conduct that lawmakers have determined warrants government enforcement and potential punishment.
Deterring unlawful conduct
Criminal penalties can discourage individuals from engaging in prohibited conduct.
Holding offenders accountable
When the government proves all required elements of an offense beyond a reasonable doubt, criminal law provides a framework for imposing legally authorized consequences.
Protecting legal rights
Criminal procedure also places limits on government power and establishes protections for people accused of crimes.
These protections are an important part of the criminal justice system because an accusation alone is not proof of guilt.
Criminal Law Research: What Do the Numbers Show?
Federal court statistics provide useful insight into the volume and types of criminal cases handled by the federal judiciary.
According to the U.S. Courts’ Judicial Business 2023 report, U.S. district courts recorded 66,147 criminal defendant filings in fiscal year 2023, including defendants transferred from other districts. That represented a 3 percent decrease from the previous year. The federal courts reported 72,371 criminal defendant terminations and 117,056 pending criminal defendants at the end of the fiscal year.
The federal judiciary’s detailed statistics also show that drug-related prosecutions represented a substantial share of federal criminal filings. In 2023, drug offenses accounted for approximately 28 percent of criminal defendant filings in the U.S. district courts, with 19,207 defendants filed in that category. Firearms and explosives offenses accounted for 10,635 defendants, while property offenses accounted for 7,140.
Research source: U.S. Courts – Federal Judicial Caseload Statistics 2023
These figures describe federal district court activity and should not be interpreted as a complete count of all criminal cases in the United States. State courts handle a large portion of criminal prosecutions, and federal court statistics measure defendants rather than providing a nationwide count of every criminal allegation.
Why Legal Representation Matters in Criminal Cases
Criminal charges can carry consequences that extend well beyond a potential fine or sentence.
Depending on the offense and the individual’s circumstances, a criminal case may affect:
- Employment.
- Professional licenses.
- Housing.
- Immigration status.
- Family relationships.
- Reputation.
- Financial circumstances.
- Future educational or career opportunities.
A criminal defense attorney can review the specific charges, evidence, applicable law, procedural issues, and potential defenses.
The appropriate legal strategy depends on the individual facts of a case. General information about criminal law cannot substitute for advice from an attorney who can review the actual circumstances.
Common Misunderstandings About Criminal Law
“Being arrested means someone is guilty.”
No. An arrest is not the same as a conviction. A defendant is generally presumed innocent unless the government proves the required offense beyond a reasonable doubt.
“All crimes are federal.”
No. Many criminal matters are prosecuted under state law. Federal prosecution requires federal jurisdiction.
“Every criminal case goes to trial.”
No. Criminal cases can be resolved in several ways, including guilty pleas and other dispositions.
“A criminal charge and a criminal conviction are the same thing.”
No. A charge is an allegation. A conviction generally follows a guilty plea or a finding of guilt through the applicable legal process.
What Is Criminal Law? Key Points to Remember
What Is Criminal Law? At its core, it is the body of law that identifies prohibited conduct as criminal and establishes the legal consequences and procedures associated with those offenses.
The most important points to remember are:
- Criminal law differs from civil law.
- Criminal statutes exist at both state and federal levels.
- The elements of an offense depend on the applicable law.
- Prosecutors generally must prove the required elements beyond a reasonable doubt.
- Felonies and misdemeanors can carry different levels of punishment.
- A criminal charge is not the same as a conviction.
- Federal courts only handle criminal matters within federal jurisdiction.
- The specific law and procedure can vary significantly by state and offense.
Final Thoughts
Understanding What Is Criminal Law? is a useful starting point for anyone trying to understand the U.S. criminal justice system. Criminal law defines prohibited conduct, establishes potential penalties, and provides procedures for prosecuting alleged offenses.
Because the United States has both state and federal criminal laws, the rules that apply to a particular case can depend on the location, alleged conduct, applicable statute, and jurisdiction involved.
If you or someone you know is facing criminal charges, general online information should not be treated as a substitute for legal advice. A qualified criminal defense attorney can evaluate the specific facts and explain the laws and procedures that apply to the individual case.
Note: This article is for general educational purposes and does not constitute legal advice. Criminal laws and procedures vary by jurisdiction and can change over time. For advice concerning a specific legal matter, consult a licensed attorney in the relevant jurisdiction.