Which case upheld state regulation of private property for the public welfare in the late 19th century?

• A. Barron v. Baltimore (1833)
• B. Katz v. United States (1967)
• C. United States v. Morrison (2000)
• D. Munn v. Illinois (1877)

Answer: (D)

The key idea is that states can use their police power to regulate private property when its use serves the public interest. Munn v. Illinois (1877) is the classic case showing this: Illinois passed laws setting maximum rates for grain elevators, which were privately owned but essential to commerce. The Supreme Court held that when private property is used in a business that affects the public welfare, the state may regulate it without violating property rights. This establishes the public-interest doctrine: property isn’t free from regulation simply because it’s privately owned if its use is important to the public. The decision hinges on balancing private property rights against the need to prevent exploitation and ensure fair access to essential services.

Other listed cases come from different times or address different issues (Barron v. Baltimore concerns applying the Bill of Rights to states; Katz v. United States deals with Fourth Amendment protections; United States v. Morrison involves federal limitations on criminal statutes).