Supreme Court of the United States
512 U.S. 374 (1994)
One of the principal purposes of the Takings Clause to bar government from forcing some people alone to bear public burdens, which in all fairness and justice, should be borne by the public as a whole.
State and local governments may engage in land use planning. Government could hardly go on, however, if to some extent values incident to property could not be dimished without paying for every such change in the general law.
Government may not require a person to give up a constitutional right in exchange for a discretionary benefit conferred by the government where the benefit sought has little or no relationship to the property.
The first question is whether an essential nexus (or link) exists between a legitimate government interest and the condition exacted. If such a link exists, the next question is the degree of connection between the exaction and projected impact of the proposed development. An exaction must be roughly proportionate to the impact attributable to the proposed development.