The Fourth Amendment: Emergency Exceptions to the Warrant Requirement
Summary
Information as of July 14, 2026. Prepared by Dave S. Sidhu, Legislative Attorney, Cassandra J. Barnum, Legislative Attorney and
Jamie Bush, Visual Information Specialist.
1 U.S. CONST. amend. IV.
2 Skinner v. Railway Labor Executives' Ass'n, 489 U.S. 602, 619 (1989).
3 Katz v. United States, 389 U.S. 347, 357 (1967).
4 United States v. Jones, 565 U.S. 400, 405–406 (2012).
5 United States v. Jacobsen, 466 U.S. 109, 113 (1984).
6 Illinois v. Gates, 462 U.S. 213, 238 (1983).
7 Terry v. Ohio, 392 U.S. 1, 29-30 (1968).
8 Illinois v. McArthur, 531 U.S. 326, 328 (2001).
9 CRS Legal Sidebar LSB10499, "No-Knock" Warrants and Other Law
Enforcement Identication Considerations, by Peter G. Berris and
Michael A. Foster (2020), at *3.
10 Kirk v. Louisiana, 536 U.S. 635, 638 (2002).
11Caniglia v. Strom, 593 U.S. 194, 197–98 (2021).
12 Mincey v. Arizona, 437 U.S. 385, 392 (1978).
13 See Case v. Montana, 607 U.S. 107, 117 (2026) ("[W]e note that an
emergency-aid entry provides no basis to search the premises beyond what
is reasonably needed to deal with the emergency while maintaining the
ocers' safety.").
14 Id. at 116.
Emergency Exceptions
to the Warrant Requirement
The Fourth Amendment protects the "right of the people" against unreasonable searches and seizures.1 The Supreme
Court has held that a search or seizure without a warrant is generally not reasonable.2 The Court has recognized,
however, certain "well-delineated" exceptions to the warrant requirement.3 This infographic clari-es the dierences
between a few of these emergency-related exceptions: exigent circumstances, community caretaking, and
emergency aid.
Key Terms and Concepts
Emergency-Related Exceptions
A Fourth Amendment
"search" generally involves
government:
• intrusion upon a person's
reasonable expectation
of privacy, or
• trespass upon a
constitutionally
protected space.4
A Fourth Amendment
"seizure" generally involves
the meaningful government
interference with a person's
possessory interests in
property or self.5
The Fourth Amendment
provides that "no Warrants
shall issue, but upon probable
cause." Probable cause
generally requires a "fair
probability" that a search will
reveal evidence of criminal
activity or that a seizure is of a
person who committed a
crime.6
Law enforcement
responsibilities include
duties:
• preventing and
investigating criminal
activity, including by
preserving evidence of
such activity, and7
• promoting public safety.8
Involves traditional crime-related functions
Probable cause required for warrantless entry into a home.10
Features
The "community caretaking" exception recognizes that law enforcement may perform
certain non-crime-related "civic functions," such as responding to disabled vehicles and
accidents.11
Features
Involves non-crime-related, civic-related functions
Does not alone justify warrantless entry into a home
The "emergency aid" exception applies when law enforcement responds to emergency
or crisis situations in which an individual poses an immediate threat to themselves or
others, or in which a person is in need of immediate medical attention.12
Features
Involves non-crime-related, crisis situations13
Probable cause not required; a warrantless entry into a home must be
supported by an "objectively reasonable basis" to believe someone inside has
been or is about to be seriously injured.14
The "exigent circumstances" exception captures situations in which law enforcement is
performing a crime-related function, such as preserving evidence, and taking the time to
secure a warrant would frustrate those crime-related interests.9