Written by attorneys · grounded in primary & secondary sources — see below
The inherent authority of a sovereign state to enact and enforce laws protecting public health, safety, morals, and general welfare. This power permits regulation of land use, business activity, and personal conduct without payment of compensation, provided the measures bear a reasonable relation to those public purposes and respect constitutional limits such as due process.
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How it applies
Common Examples
6
Zoning Limits Residential Development
Preston Pratt purchased a large tract intending to build a commercial complex. The city then enacted a zoning ordinance dividing the area into residential districts and barring commercial uses. The ordinance operates as a valid exercise of police power because the classification reasonably advances public health and general welfare by controlling density and traffic. Pratt's challenge fails because the restriction leaves him with economically viable residential use of the land.
Defamation Liability And State Interests
Penelope Price, a private attorney, sued a magazine for publishing false statements about her professional conduct. The magazine argued that First Amendment protections barred recovery absent proof of actual malice. The court applied state libel rules that reflect the police power to protect individual reputation, allowing recovery on a negligence standard because Price was not a public figure. This outcome shows how the police power supports private tort remedies without conflicting with constitutional speech guarantees.
Gertz v. Robert Welch, Inc.418 U.S. 323, 94 S. Ct. 2997, 41 L. Ed. 2d 789 (1974)
Landmark Designation Restricts Redevelopment
Pierre Poulin owned a historic train terminal and sought to build a large office tower above it. The city designated the terminal a landmark and barred the proposed construction. The restriction functions as an exercise of police power to preserve the public interest in historic structures. Poulin retains the terminal's current use, so the measure does not constitute a taking despite reducing potential profits.
Penn Central Transportation Co. et al. v. New York City438 U.S. 104, 98 S.Ct. 2646, 57 L.Ed.2d 631 (1978)
Zoning Defines Family Occupancy
Paige Porter, a grandmother, moved in with her grandchildren after their mother died. City zoning limited dwelling occupancy to members of a single nuclear family, excluding her arrangement. The ordinance reflects an exercise of police power aimed at preserving neighborhood character and stability. The restriction is invalid because it draws an irrational distinction unrelated to any legitimate public purpose.
Moore v. City of East Cleveland, Ohio431 U.S. 494, 503 (1977)
Labor Regulation Exceeds Police Power
Priscilla Parks owned a bakery and scheduled bakers for shifts longer than ten hours per day. A state statute limited bakery employees to ten hours daily to protect worker health. The law was struck down because it exceeded the legitimate scope of police power by interfering with freedom of contract without a sufficient connection to public welfare.
Lochner v. New York198 U.S. 45 (1905)
Street Widening Requires Compensation
Phoenix Technologies owned a rail yard abutting a city street. The city widened the street and took a strip of the yard for the improvement. The action required payment of just compensation because the taking went beyond mere regulation under the police power and instead appropriated private property for public use.
Chicago, Burlington & Quincy Railroad Co. v. City of Chicago166 U.S. 226, 239, 17 S.Ct. 581, 585, 41 L.Ed. 979 (1897)
Common questions
Frequently Asked
5
Does the federal government possess a general police power?+
No. The federal government lacks a general police power to regulate solely for the health, safety, or welfare of citizens. Each federal action must rest on an enumerated power in the Constitution, unlike states which hold inherent police power.
When does land-use regulation cross from police power into a taking?+
A regulation remains within police power and requires no compensation when it leaves the owner with economically viable use and advances a legitimate public purpose. It becomes a taking when it denies all economically viable use or fails the multi-factor balancing test that weighs economic impact, investment-backed expectations, and the character of the action.
Can states use police power to require vaccination?+
Yes. Compulsory vaccination laws are valid exercises of the police power when they protect public health and safety from contagious disease. Such measures may override individual objections provided they are reasonable and do not violate other constitutional protections.
How does police power relate to zoning ordinances?+
Zoning ordinances that divide land into districts and restrict uses are valid exercises of police power when the classifications are reasonable and substantially related to public health, safety, morals, or general welfare. Courts uphold comprehensive zoning schemes that meet this standard.
Does the police power allow states to regulate purely intrastate activity?+
Yes. States may regulate intrastate matters affecting health, safety, and welfare under their inherent police power. This authority remains subject to federal preemption or specific constitutional limits but is otherwise broad.
to protect the public interest in such landmarks. Pp. 135-138. Majority opinion Opinion of Justice Brennan The question presented is whether a city may, as part of a comprehensive…
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State
s" are not displaced by a federal statute "unless that was the clear and manifest purpose of Congress"); Florida Lime & Avocado Growers, Inc. v. Paul , 373 U. S. 132, 146…
. It does not violate any fundamental right protected by the Due Process Clause. The right to live with one’s grandchildren is not a fundamental liberty interest protected by the…
State
. 376 U. S., at 273-276.[^maj-24] In a democratic society such as ours, the citizen has the privilege of criticizing his government and its officials. But neither New York…
Constitutional LawThe separation of powers · The powers of CongressUBEFoundational