What is the Fourth Amendment?

What is the Fourth Amendment?

It says that:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

These 54 words have spawned thousands of appellate opinions, law review articles, and books interpreting them – why is the Fourth Amendment so important, why do we have it, and how is it applied in criminal cases?

Why Do We Have the Fourth Amendment?

In Colonial America, there was apparently a problem with smugglers who were sneaking goods past the customs officers. The Crown’s solution was to issue “writs of assistance” to customs officers, which allowed them to search a person or their property without providing a reason and without being responsible for any damage that they caused.

Merchants in Boston filed a lawsuit, arguing that “a man’s house is his castle,” and the colonists’ rights as Englishmen were being violated by the writs, but the court disagreed and ruled against them. The continued use of the writs led to conflict, with some merchants refusing to comply when customs agents sought to search their homes or ships.

These writs of assistance, along with the many other abuses by the Crown against the people of the colonies, led to the American Revolution and helped to shape our Constitution and Bill of Rights.

Following the revolution, several colonies included a “particularity requirement” for warrants in their constitutions. When the Bill of Rights was passed, the Fourth Amendment to the US Constitution also included a particularity requirement, effectively banning the use of writs of assistance or “general warrants” by the federal government.

In Mapp v. Ohio, in 1961, the US Supreme Court held that the Fourth Amendment applies to state and local governments as well as the federal government under the Due Process Clause of the Fourteenth Amendment.

The Fourth Amendment Prohibits Unreasonable Searches and Seizures

The Fourth Amendment protects “against unreasonable searches and seizures,” but what is unreasonable?

If you are committing a crime or have evidence of a crime in your possession, in your car, or in your home, the government has the right to search, seize evidence, or take you into custody. But the government must know that you are committing a crime or that evidence in your possession – they don’t get to search anyone they like or make arrests without probable cause.

A search or seizure is reasonable if the government has probable cause to search, to seize evidence, or to arrest a person. They must be able to demonstrate that there is some evidence, less than would be required to convict a person but more than a mere suspicion, that a crime has occurred or that evidence will be found before they can enter your home, take your possessions, or arrest you.

What is a search for purposes of the Fourth Amendment?

In recent years, the US Supreme Court has defined a “search” as an event where the government violates a person’s reasonable expectation of privacy. This could include:

  • A search of your home,
  • A search of your person,
  • A search of your automobile,
  • Entering your property without a warrant,
  • Wiretaps on your phones, or
  • Tracking devices placed on your vehicle.

What is a seizure for purposes of the Fourth Amendment?

A seizure is when a government agent takes something from you or restricts your freedom of movement. Some examples include:

  • A custodial arrest, where they put handcuffs on you and put you in a jail cell,
  • A detention where you are not free to leave, even if you are not locked in a jail cell,
  • A government taking of your home, your vehicle, or other property that belongs to you, or
  • A government taking of any property that could later be used as evidence against you.

The Fourth Amendment Requires a Warrant (Except When It Doesn’t)

A search or seizure must be reasonable. Reasonable means that the government must have probable cause before searching or seizing you or your property. In many cases, the government must also have a warrant before searching or seizing property.

The “starting point” for any Fourth Amendment analysis is that the government must have a warrant (although they often don’t need a warrant, see below). No warrant is valid unless it:

  • Is based upon probable cause,
  • Is supported by “oath or affirmation” (the “warrant affidavit” section of an arrest or search warrant),
  • Particularly describes the place to be searched (address and a physical description in most cases), and
  • Particularly describes the persons or things that will be seized (the person being arrested or the specific type of evidence for which police are searching).

Although the Constitution implies that a warrant is required before the government can conduct a search or seizure, the only requirement is that the search and seizure not be unreasonable.

The courts have interpreted this to mean that police must be able to show probable cause before searching or seizing property, and Fourth Amendment law is now littered with exceptions to the warrant requirement. For example:

  • The automobile exception allows police to search your vehicle without first getting a warrant;
  • Police are allowed to make arrests for certain misdemeanor offenses that are committed in their presence (or “freshly committed”) without an arrest warrant, although they may be required to seek a warrant after the arrest is made;
  • Police are allowed to make arrests for certain misdemeanor or traffic offenses on a citation without ever getting an arrest warrant;
  • If you consent to a search, police do not have to seek a search warrant;
  • If police see contraband “in plain view,” they do not have to get a search warrant before seizing the contraband;
  • Police are permitted to frisk a person for weapons under Terry v. Ohio without first getting a warrant;
  • Searches “incident to arrest” are permitted when a person is being taken into custody;
  • Border searches can be conducted without a warrant (and without probable cause);
  • Public schools and prisons can be searched without a warrant; and
  • “Exigent circumstances” may justify a search without a warrant (evidence will be destroyed if police leave to seek a warrant, police are in “hot pursuit” of a suspect who runs into a home, or someone’s life is in danger).

In most cases, if police do not seek a warrant before searching, they must still justify the search later in court by showing that they had probable cause before conducting the search or seizure.

How is the Fourth Amendment Enforced?

Why is the Fourth Amendment so important in criminal defense cases?

It is enforced through what is called “the exclusionary rule.” If police violate your Fourth Amendment rights by conducting a search without probable cause (or without a warrant in some cases), the remedy is exclusion of that evidence from your trial.


Because there is no other practical way to enforce your constitutional rights. Law enforcement is not going to voluntarily respect the constitutional rights of citizens. Law enforcement leadership is not going to punish officers who violate the constitutional rights of citizens.

Although violating your constitutional rights may also be a crime, no one is going to arrest and prosecute police officers who violate your constitutional rights.

If you sue a police officer for violating your constitutional rights, you have an uphill battle to prove that the officer is not entitled to qualified immunity and to persuade a judge and jurors that the police officer should be punished or should be forced to compensate you.

If you sue a police officer for violating your Fourth Amendment rights when they actually found drugs or some other contraband, no jury is going to rule in your favor, you may not be able to show damages, and there is no remedy other than exclusion of the evidence.

Criminal Defense Lawyer in Charleston, SC

Charleston, SC criminal defense attorney Grant B. Smaldone represents people charged with crimes in SC state and federal courts.

If you have been charged with a crime or believe that you are under investigation in the Charleston, Georgetown, or Myrtle Beach areas of SC, call now at (843) 808-2100 or send an email to schedule a free consultation.