Defense of Property

In most states, individuals generally have the right to defend themselves from unlawful physical force. An analogous extension of this right of self-defense is the right to protect property from trespassers. This right may relieve a property owner of liability for actions that would otherwise be considered either an actionable tort or a crime. As with the right of self-defense, the nature and limits of the right to defend property are largely a creation of state law, and therefore vary among different jurisdictions.  

Definition of Trespasser

State statutes generally employ varying language when defining a "trespasser."  Many have adopted or modified definitions included in legal treatises, such as that included in the Restatement of Torts, Second, which defines a trespasser as "a person who enters or remains upon land in the possession of another without a privilege to do so created by the possessor's consent or otherwise."  The following are sample definitions from different state statutes defining a trespasser:

• The California Penal Code provides several definitions that are similar in many respects to the statutes of other states.  In California, a trespasser may include any of the following: 1) One who enters lands for purpose of injuring property or property rights, or to interfere with business; 2) One who refuses to leave property on request of a peace officer, owner, owner's agent, or person in lawful possession; or 3) One who enters or remains in a dwelling house or residence without consent of owner, agent, or person in lawful possession.
  
  
• The relevant Florida criminal trespass statute states that "whoever, without being authorized, licensed, or invited, willfully enters or remains in any structure or conveyance, or, having been authorized, licensed, or invited, is warned by the owner or lessee of the premises, or by a person authorized by the owner or lessee, to depart and refuses to do so, commits the offense of trespass in a structure or conveyance."
  
  
• The Texas Penal Code states that "a person commits [criminal trespass] if he enters or remains on or in property, including an aircraft or other vehicle, of another without effective consent or he enters or remains in a building of another without effective consent and he: 1) had notice that the entry was forbidden or 2) received notice to depart but failed to do so." This statute continues with specific definitions of "entry" and "notice."

Defending Property Through the Use of Force

Property owners are generally allowed to use reasonable force, (e.g., force not intended to cause death or serious bodily harm), against an intruder on the owner's property. Reasonable force is generally only the amount of force necessary to repel or expel the trespasser.  According to the Restatement of Torts, a possessor of land is privileged to use "a mechanical protective device for protection of his property to the same extent he is entitled to use a watchdog."  Such items might include (subject to state law limitations) barbed wire, fence spikes, and broken glass. 

State laws differ substantially with respect to the types of items that are considered non-deadly, as well as the types of conduct that may be considered acceptable.  Items such as broken glass or mace are often considered preventative and may be deemed non-deadly, depending on jurisdiction.  Many state statutes explicitly list the types of items that are prohibited.  Further, even the extent to which such devices are prohibited may vary by state.  The following illustrates such differences with respect to "stun guns"- an item considered deadly in many states:

• The relevant New Jersey statute states that "Any person who knowingly has in his possession any stun gun is guilty of a crime of the fourth degree."  Crimes in New Jersey classified as fourth degree offenses carry a maximum of one year of incarceration, if committed by an adult.
  
  
• Massachusetts law is more specific than New Jersey's and holds that "No person shall sell, offer for sale or possess a portable device or weapon from which an electrical current, impulse, wave or beam may be directed, which current, impulse, wave or beam is designed to incapacitate temporarily, injure or kill."  Persons found in violation of this law face a minimum fine of $500 or a minimum jail term of six months.
  
  
• The Michigan Penal Code includes language that is substantially similar to that used in Massachusetts.  It states that "a person shall not sell, offer for sale, or possess in this state a portable device or weapon from which an electrical current, impulse, wave, or beam may be directed, which current, impulse, wave, or beam is designed to incapacitate temporarily, injure, or kill."  The penalty for violating this statute includes a maximum prison sentence of four years and/or a $2000 fine.

In most states, devices that are considered dangerous weapons are generally not permitted, such as spring guns and traps.  A well-known 1970 case, Katko v. Briney, resulted in a property owner being subject to liability for injuring a trespasser with a spring gun.  In Katko, the Iowa Supreme Court noted that "the law has always placed a higher value on human safety than upon mere rights in property."  The court further indicated that there is generally "no privilege to use any force calculated to cause death or serious bodily injury to repel the threat to land or chattels, unless there is also such a threat to the defendant's personal safety as to justify self defense."  Similar principles are still applicable today, and as a general rule deadly force may not be used to defend property unless there is a threat of the loss of life or serious bodily injury.