In tortcommon law, the defense of necessity gives the state or an individual a privilege to take or use the property of another. A defendant typically invokes the defense of necessity only against the intentional torts of trespass to chattels, trespass to land, or conversion. The Latin phrase from common law is necessitas inducit privilegium quod jura privata. A court will grant this privilege to a trespasser when the risk of harm to an individual or society is apparently and reasonably greater than the harm to the property. Unlike the privilege of self-defense, those who are harmed by individuals invoking the necessity privilege are usually free from any wrongdoing. Generally, an individual invoking this privilege is obligated to pay any actual damages caused in the use of the property but not punitive or nominal damages.
Private necessity
Private necessity is the use of another's property for private reasons. Well established doctrines in common law prevent a property owner from using force against an individual in a situation where the privilege of necessity would apply. While an individual may have a private necessity to use the land or property of another, that individual must compensate the owner for any damages caused. For example: In American law, the case most often cited to explain the privilege of private necessity is Vincent v. Lake Erie Transp. Co., 109 Minn. 456, 124 N.W. 221.
;Facts ;Issue ;Decision ;Dissent To invoke the private necessity privilege, the defendant must have been actually threatened or have reasonably thought that a significant harm were about to occur. The ruling in Vincent v. Lake Erie assures private citizens from a public policy standpoint that they will be compensated for their loss. Vincent will be compensated for repairs and Lake Erie can rest assured that their ship will not sink.
Public necessity
Public necessity is the use of private property by a public official for a public reason. The potential harm to society necessitates the destruction or use of private property for the greater good. The injured, private individual does not always recover for the damage caused by the necessity. In American law, two conflicting cases illustrate this point: Surocco v. Geary, 3 Cal. 69 and Wegner v. Milwaukee Mutual Ins. Co.479 N.W.2d 38.
''Surocco v. Geary''
;Facts ;Issue ;Decision The decision in Surocco v. Gearydiffers from the private necessity doctrine that a trespasser must compensate a property owner for any damage she may cause.
''Wegner v. Milwaukee Mutual Ins. Co.''
This case coincides with the private necessity doctrine and shows that American courts are conflicted on the issue of compensation for damage. ;Facts ;Issue ;Decision It is an issue of public policy to determine if either private individuals or the public at large through taxes should bear the loss for damages caused through public necessity. Wegner v. Milwaukee allocates the loss that benefits the public to the public rather than to Wegner, the innocent citizen. Cases with similar facts to Wegner have used the public necessity doctrine under Surocco, and the individual must bear the cost of the greater public good. Courts determine this issue as a matter of public policy.
