The Fourth Amendment to the United States Constitution

The Fourth Amendment

The Constitution defines the Fourth Amendment as, “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.”

In layman’s terms, this means that the government (police) must have probable cause to arrest you or reasonable suspicion of criminal activity to detain you. With some limited exceptions, it also means that police must have probable cause to search you, your home, your workplace, or your vehicle. Sometimes a warrant is required and at other times there is an exception to the warrant requirement.

What is probable cause?

Probable cause has been defined by the United States Supreme Court as, “reasonable ground of suspicion supported by circumstances sufficiently strong in themselves to warrant a cautious man in the belief that the party is guilty of the offense with which he is charged.” Dumbra v. United States, 268 U.S. 435 (1925)

How does law enforcement get probable cause?

Probable cause can be derived from a variety of sources.

Information – statements given by witnesses or victims.

Observation – information gathered by an officer’s inspection or examination.

Sensory – an officer can detect evidence of a crime through sight, sound, or smell.

Expertise – an officer can rely on personal background to evaluate the possibility of criminal activity.

What can law enforcement do under the Fourth Amendment?


An arrest can occur when a law enforcement officer uses legal authority to restrict a suspect’s freedom of movement. However, to make an arrest the police must have probable cause.


Police must have reasonable suspicion that criminal activity has taken place before detaining a person. Detaining someone requires a lower level of proof of criminal activity than probable cause. This is known as reasonable suspicion. The United States Supreme Court lays out the requirements for detention in Terry v. Ohio, 392 U.S. 1 (1968).

Search warrants

To obtain and initiate a search warrant, an officer must have probable cause. A law enforcement officer must ultimately present an affidavit to a judge or magistrate to obtain a search warrant. However, there are exceptions to these requirements, and many searches can take place without a warrant. For instance, one such exception is for the search for an automobile. This is known as the Carroll doctrine from the United States Supreme Court case Carroll v. United States, 267 U.S. 132 (1925). In addition, another exception is search incident to arrest. Under this exception, if police have probable cause to arrest, they can also search the individual being arrested. 

Contact Wichita’s Criminal Defense Attorney

We are a trusted and experienced defense attorney team at Koop Law Firm. If you have been arrested and are facing charges based on a search that was done with or without a warrant, contact us today.

The information provided in this article does not constitute legal advice; it is for general informational purposes only.

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