In Murr v. Wisconsin, the U.S Supreme Court was tasked with determining how to define "the parcel as a whole" for purposes of regulatory takings analysis under the Fifth Amendment's Takings Clause. The Murrs owned two adjacent lots in Wisconsin and sought to sell one of them but were prevented from doing so by state law and local ordinance which treated contiguous properties under common ownership as a single property that could not be separately sold or developed if it failed to meet size requirements. The Murrs argued this constituted an uncompensated taking of their property, violating their constitutional rights. However, the court ruled against them in 2017 in a 5-3 decision stating that both parcels should be considered together when evaluating whether regulations have gone too far and resulted in a compensable taking. This ruling clarified that courts must consider several factors including treatment of land under state/local laws, physical characteristics & prospective value when defining 'property' for takings clause purposes.

In the dissenting opinion for Murr v. Wisconsin, Chief Justice Roberts, joined by Justices Thomas and Alito, argued that the majority's ruling blurred established property rights principles and created confusion rather than clarity. The dissenters disagreed with the majority's "parcel as a whole" concept to determine whether a taking has occurred. They believed this approach was inconsistent with prior case law which treated separate lots as distinct pieces of property for takings analysis purposes. Instead, they proposed an approach where courts should look at state law to define the boundaries of distinct parcels of land before determining if there has been a regulatory taking. This would provide clear rules on what constitutes private property under Fifth Amendment’s Takings Clause without requiring complex factual assessments about reasonable expectations regarding land use regulations.