4th Amendment

When the government suspects someone of committing a crime, they can't just barge into someone's house or hack into their computer to look for evidence, right? The 4th Amendment provides some protections against this by requiring the government to establish probable cause and obtain a warrant before it can search or seize. This right has been very important throughout American history and is still being interpreted by the Supreme Court!

4th Amendment 4th Amendment

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Table of contents

    4th Amendment Rights

    The Fourth Amendment to the Constitution is the first of the "rights of the accused" section, which constitutes the Fourth Amendment, Fifth Amendment, and Sixth Amendment. The Fourth Amendment gives people the right to be safe from unreasonable government searches or property seizures. It requires the government to obtain warrants that show probable cause before search or seizure.

    Seizure, in this context, refers to when government officials take someone's property (which can include evidence, papers, data, etc.), usually during a criminal investigation.

    4th Amendment Examples

    Like other provisions like the Second Amendment and Third Amendment, the inspiration for the Fourth Amendment can be traced to events in British history.

    Semayne Case

    The first trace of the Fourth Amendment is Semayne's Case in 1603. The case centered around two men who lived together in London. After one of them died while in debt to a man named Peter Semayne, Semayne tried to seize his goods. When he was denied entry, he sued the roommate for his losses.

    In respones, the court provided some protections against breaking and entering a house. Sir Edward Coke famously said that a man's house is his castle and fortress.

    Entick v. Carrington

    In 1762, messengers sent by the king's Secretary of State broke into writer John Entick's house in England. They ransacked the home and search it from top to bottom, causing significant damage and seizing a few hundred pamphlets as evidence of Entick's sedition. Entick sued them for trespassing.

    4th Amendment John Entick StudySmarterFig. #1 A portrait of author John Entick. Source: Guillaume Philippe Benoist, Wikimedia Commons, PD-Art

    The court ruled in his favor, saying that neither the Secretary of State nor the men who carried out his orders had the authority to issue a warrant for Entick's home. Their decision was rooted in the right to property, saying:

    The great end, for which men entered into society, was to secure their property... By the laws of England, every invasion of private property, be it ever so minute, is a trespass.1

    This case was later cited by the United States Supreme Court as one of the foundations for the Fourth Amendment.

    Right to Property

    Many of the rights within the Bill of Rights come back to the idea of the right to property, but the concept of property rights was still relatively new, originating in the 17th Century.

    The right to property was revolutionary because for much of European history, only nobles and aristocrats owned land. Commoners often worked very hard, but instead of reaping the benefits of their labor, a large portion went to the noble who owned the land. The other side of owning something means that no one else can take it away or claim it as their own. If you write a newspaper criticizing the government, the police aren't allowed to break into your print shop and take your equipment.

    4th Amendment Summary

    The American colonists also began seeking protections from the British government's search and seizure.

    James Otis and Writs of Assistance

    While people in England enjoyed some wins related to protecting their personal property from government intrusion, many of those same rights didn't apply to colonists in the Americas. This, along with new laws increasing colonists' taxes, ultimately led to the American Revolution and the passage of the Fourth Amendment.

    In the 1760s, British officials began cracking down on suspected smuggling in the American colonies. Officials simply had to obtain a writ of assistance to get the authority to search and seize colonial property.

    A writ of assistance (also called a general warrant), used in colonial Britain and America, gave officials the authority to search anywhere at any time for smuggled goods. Unlike other warrants, they weren't limited to a specific property or expiration date.

    The colonists were outraged. James Otis, a lawyer from Massachusetts, led a movement to oppose the writs of assistance in court. He argued that they violated British law, and famously said:

    [the writ of assistance] appears to me the worst instrument of arbitrary power, the most destructive of English liberty and the fundamental principles of law, that ever was found in an English lawbook."2

    While the courts ruled against Otis, his words inspired many revolutionaries to resist oppressive British policies.

    Virginia Declaration of Rights

    When the United States declared independence in 1776, several states began issuing their own declaration of rights. In particular, Virginia's Declaration of Rights helped lead to the Fourth Amendment, as it stated that general warrants are "grievous and oppressive and ought not to be granted."3

    Constitution 4th Amendment

    After winning the war, Congress eventually came back together in 1787 to draft a new constitution. However, several states refused to ratify the Constitution unless Congress added a Bill of Rights.

    Thus, the Bill of Rights, along with the Fourth Amendment, was ratified in 1791. Below is the full text of the Fourth Amendment:

    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.

    4th Amendment Protections

    There are two important requirements that protect individuals: Warrants and Probable Cause.


    A warrant is an official document authorization officials to do something, such as searching and/or seizing property. To obtain a warrant, police officers must establish probable cause and provide the proper documentation to a magistrate, who then decides whether or not to issue the warrant. There are a few exceptions that allow officers to search or seize property without a warrant (see below!).

    Probable Cause

    In order to obtain a warrant, investigators must establish probable cause. Probable Cause means that there is a strong amount of evidence and facts to lead investigators to believe that the subject has committed a crime. This also means that officials can't just request a warrant for every suspicious person they see.


    There are a few exceptions to the requirement for officials to obtain a warrant and establish probable cause. These include:

    • If the subject consents to a search;
    • If the evidence is in "plain view and open field," meaning that the evidence can be observed out in public;
    • In the presence of "exigent circumstance," meaning that entry was necessary to prevent physical harm, destruction of evidence, or the suspect's escape;
    • If the officer has probable cause to believe that evidence or contraband is in a motor vehicle;
    • If the subject is close (within 100 miles) to a United States border.

    4th Amendment Cases

    In the past century, several important Supreme Court cases have added to our understanding of the 4th Amendment.

    Week v. United States and the Exclusionary Rule

    In 1911, a man named Fremont Weeks was arrested for using the mail to send lottery tickets. Police officers searched his home without a warrant, seized a number of papers, and handed them over to the marshall to submit as evidence. After Weeks was convicted using this evidence, he sued the court, saying that the officers had violated the 4th Amendment.

    The Supreme Court agreed with Weeks and said that since the officers didn't obtain a warrant, the evidence couldn't be used in court. In doing so, they established the exclusionary rule.

    The exclusionary rule says that any evidence that is obtained without using the proper legal process (i.e. obtaining a warrant) can't be used in court, even if the evidence proves that a crime was committed.

    Olmstead v. United States (1928)

    In 1928, a man named Roy Olmstead challenged his conviction for a crime because the evidence used to convict him came from wiretapped private phone conversations. He argued that the secret wiretap violated his 4th Amendment rights.

    The Supreme Court ruled against him, saying that "search and seizure" only applied to physical property.

    4th Amendment Wiretapping devices StudySmarterFig. #2 Wiretapping devices allow investigators to listen in on phone conversations. Source: Paul2, Wikimedia Commons, CC-BY-SA-4.0

    Katz v. United States (1967)

    Several decades later, the Supreme Court overturned the Olmstead decision in Katz v. United States. They said that the Fourth Amendment does cover phone conversations, which meant that the police needed to obtain a proper warrant before wiretapping.

    4th Amendment - Key takeaways

    • The 4th Amendment requires the government to establish probable cause and obtain a warrant before it can proceed to search and seizure of property.
    • The roots of the 4th Amendment go back to 17th Century England and colonial America as the understanding of the right to property developed.
    • The Exclusionary Rule, established by the Supreme Court in 1911, says that evidence that doesn't comply with the 4th Amendment can't be used in court.
    • While the Olmstead case initially shrunk the 4th Amendment protections, the Katz case in 1967 clarified that it applies to non-physical property like phone conversations.


    1. Lord Camden, Entick v. Carrington Opinion, 1762
    2. James Otis, Speech, Against Writs of Assistance, 1761
    3. Virginia Declaration of Rights, 1776
    Frequently Asked Questions about 4th Amendment

    What is the 4th Amendment?

    The 4th Amendment is a provision in the Bill of Rights protecting citizens against unreasonable search and seizure.

    When was the 4th Amendment ratified?

    The 4th Amendment was ratified in 1791 along with the rest of the Bill of Rights.

    Why was the 4th Amendment created?

    The 4th Amendment was created to protect citizens from unreasonable search and seizure.

    What does the 4th Amendment protect?

    The 4th Amendment protects people from having their property searched or seized by the government. It also protects them by requiring public officials to obtain a warrant.

    Why is the 4th Amendment important?

    The 4th Amendment is important because it provides protection for people who are accused or suspected of wrongdoing and ensures that government officials have proper reasoning before gathering evidence against them.

    Test your knowledge with multiple choice flashcards

    The idea around the 4th Amendment goes back to

    Why did James Otis oppose writs of assistance?

    The 4th Amendment was added to the Constitution in the Bill of Rights

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