Section 601. Justification.  (1) Defense. Except as otherwise expressly provided, justification or excuse under this Chapter is a defense.

(2) Danger to Other Persons. If a person is justified or excused in using force against another, but he recklessly or negligently injures or creates a risk of injury to other persons, the justifications afforded by this Chapter are unavailable in a prosecution for such recklessness or negligence, as the case may be.

(3) Civil Remedy Unimpaired. That conduct may be justified or excused within the meaning of this Chapter does not abolish or impair any remedy for such conduct which is available in any civil action.

(4) State Prosecution of Federal Public Servant. The defenses of justification and excuse may be asserted in a state or local prosecution of a federal public servant, or a person acting at his direction, based on acts performed in the course of the public servant's official duties.

Section 602. Execution of Public Duty.  (1) Authorized by Law. Conduct engaged in by a public servant in the course of his official duties is justified when it is required or authorized by law.

(2) Directed by a Public Servant. A person who has been directed by a public servant to assist that public servant is justified in 'using force to carry out the public servant's direction, unless the action being taken by the public servant is plainly unlawful.

(3) Citizen's Arrest. A person is justified in using force upon another in order to effect his arrest or prevent his escape when a public servant authorized to make the arrest or prevent the escape is not available, if the other person has committed, in the presence of the actor, any crime which the actor is justified in using force to prevent or if the other person has committed a felony involving force or violence.

Section 603. Self-Defense.  A person is justified in using force upon another person in order to defend himself against danger of imminent unlawful bodily injury, sexual assault or detention by such other person, except that:

     (a) a person is not justified in using force for the purpose of resisting arrest, execution of process, or other performance of duty by a public servant under color of law, but excessive force may be resisted; and
     (b) a person is not justified in using force if (i) he intentionally provokes unlawful action by another person in order to cause bodily injury or death to such other person, or (ii) he has entered into a mutual combat with another person or is the initial aggressor unless he is resisting force which is clearly excessive in the circumstances. A person's use of defensive force after he withdraws from an encounter and indicates to the other person that he has done so is justified if the latter nevertheless continues or menaces unlawful action.

Section 604. Defense of Others.  A person is justified in using force upon another person in order to defend anyone else if (a) the person defended would be justified in defending himself, and (b) the person coming to the defense has not, by provocation or otherwise, forfeited the right of self-defense.

Section 605. Use of Force by Persons with Parental, Custodial or Similar Responsibilities.  The use of force upon another person is justified under any of the following circumstances:

     (a) a parent, guardian or other person responsible for the care and supervision of a minor under eighteen years old, or teacher or other person responsible for the care and supervision of such a minor for a special purpose, or a person acting at the direction of any of the foregoing persons, may use force upon the minor for the purpose of safeguarding or promoting his welfare, including prevention and punishment of his misconduct, and the maintenance of proper discipline. The force used for this purpose may be such as is reasonable, whether or not it is "necessary" as required by section 607(1), but must not be designed to cause or known to create a substantial risk of causing death, serious bodily injury, disfigurement or gross degradation;
     (b) a guardian or other person responsible for the care and supervision of an incompetent person, or a person acting at the direction of the guardian or responsible person, may use force upon the incompetent person for the purpose of safeguarding or promoting his welfare, including the prevention of his misconduct or, when he is in a hospital or other institution for care and custody, for the purpose of maintaining reasonable discipline in the institution. The force used for these purposes may be such as is reasonable, whether or not it is "necessary" as required by section 607(1), but must not be designed to cause or known to create a substantial risk of causing death, serious bodily injury, disfigurement or gross degradation;
     (c) a person responsible for the maintenance of order in a vehicle, train, vessel, aircraft, or other carrier, or in a place where others are assembled, or a person acting at the responsible person's direction, may use force to maintain order;
     (d) a duly licensed physician, or a person acting at his direction, may use force in order to administer a recognized form of treatment to promote the physical or mental health of a patient if the treatment is administered (i) in an emergency, or (ii) with the consent of the patient or, if the patient is a minor or an incompetent person, with the consent of his parent, guardian or other person entrusted with his care and supervision, or (iii) by order of a court of competent jurisdiction;
     (e) a person may use force upon another person about to commit suicide or suffer serious bodily injury in order to prevent the death or serious bodily injury of such other person.

Section 606. Use of Force in Defense of Premises and Property.  Force is justified if it is used to prevent or terminate an unlawful entry or other trespass in or upon premises, or to prevent an unlawful carrying away or damaging of property, if the person using such force first requests the person against whom such force is to be used to desist from his interference with the premises or property, except that:

     (a) request is not necessary if (i) it would be useless to make the request, or (ii) it would be dangerous to make the request, or (iii) substantial damage would be done to the property sought to be protected before the request could effectively be made;
     (b) the use of force is not justified to prevent or terminate a trespass if it will expose the trespasser to substantial danger of serious bodily injury.

Section 607. Limits on the Use of Force: Excessive Force; Deadly Force.  (1) Excessive Force. A person is not justified in using more force than is necessary and appropriate under the circumstances.

(2) Deadly Force. Deadly force is justified in the following instances:

     (a) when it is expressly authorized by a federal statute or occurs in the lawful conduct of war;
     [(a) when it is authorized by a federal law or occurs In the necessary and appropriate conduct of war;]
     (b) when used in lawful self-defense, or in lawful defense of others, if such force is necessary to protect the actor or anyone else against death, serious bodily injury, or the cow-mission of a felony involving violence, except that the use of deadly force is not justified if it can be avoided, with safety to the actor and others, by retreat or other conduct involving minimal interference with the freedom of the person menaced. A person seeking to protect someone else must, before using deadly force, try to cause that person to retreat, or otherwise comply with the requirements of this provision, if safety can be obtained thereby; but (i) a public servant or an officer of a ship or aircraft justified in using force in the performance of his duties or a person justified in using force in his assistance need not desist from his efforts because of resistance or threatened resistance by or on behalf of the person against whom his action is directed, and (ii) no person is required to retreat from his dwelling, or place of work, unless he was the original aggressor or is assailed by a person who he knows also dwells or works there;
     (c) when used by a person in possession or control of a dwelling or place of work, or a person who is licensed or privileged to be thereon, if such force is necessary to prevent commission of arson, burglary, robbery or a felony involving violence upon or in the dwelling or place of work or to prevent a person in flight immediately after committing a robbery or burglary from taking the fruits thereof from the dwelling or place of work, and the use of force other than deadly force for such purposes would expose anyone to substantial danger of serious bodily injury;
     (d) when used by a public servant authorized to effect arrests or prevent escapes, if such force is necessary to effect an arrest or to prevent the escape from custody of a person who has committed or attempted to commit a felony involving violence, or is attempting to escape by the use of a deadly wear on, or has otherwise indicated that he is likely to endanger human life or to inflict serious bodily injury unless apprehended without delay;
     (e) when used by a guard or other public servant, if such force is necessary to prevent the escape of a prisoner from a detention facility unless he knows that the prisoner is not such a person as described in paragraph (d) above. A detention facility is any place used for the confinement, pursuant to a court order, of a person (i) charged with or convicted of an offense, or (ii) charged with being or adjudicated a youth offender or juvenile delinquent, or (iii) held for extradition, or (iv) otherwise confined pursuant to court order;
     (f) when used by a public servant, if such force is necessary (i) to prevent overt and forceful acts of treason, insurrection or sabotage, or (ii) to prevent murder, manslaughter, aggravated assault, arson, robbery, burglary or kidnapping in the course of a riot if the deadly force is employed following reasonable notice of intent to employ deadly force, and does not carry with it an unreasonable danger to life of nonparticipants in the riot, and is employed pursuant to a decision or order of a public servant having supervisory authority over ten or more other public servants concerned in the suppression of the riot;
     (g) when used by an officer of a ship or aircraft if such force is necessary to prevent overt and forceful acts of mutiny, after the participants in such acts against whom such force is to be used have been ordered to cease and given reasonable notice of intent to employ deadly force;
     (h) when used by a duly licensed physician, or a person acting at his direction, if such force is necessary in order to administer a recognized form of treatment to promote the physical or mental health of a patient and if the treatment is administered (i) in an emergency, or (ii) with the consent of the patient or, if the patient is a minor or an incompetent person, with the consent of his parent, guardian or other person entrusted with his care and supervision, or (iii) by order of a court of competent jurisdiction;
     (i) when used by a person who is directed or authorized to use deadly force by a public servant or an officer of a ship or aircraft and who does not know that, if such is the case, the public servant or such officer is himself not authorized to use deadly force under the circumstances.

Section 608. Excuse.  (1) Mistake. A person's conduct is excused if he believes that the factual situation is such that his conduct is necessary and appropriate for any of the purposes which would establish a justification or excuse under this Chapter, even though his belief is mistaken, except that, if his belief is negligently or recklessly held, it is not an excuse in a prosecution for an offense for which negligence or recklessness, as the case may lie, suffices to establish culpability. Excuse under this subsection is a defense or affirmative defense according to which type of defense would be established had the facts been as the person believed them to be,

(2) Marginal Transgression of Limit of Justification. A person's conduct is excused if it would otherwise be justified or excused under this Chapter but is marginally hasty or excessive because he was confronted with an emergency precluding adequate appraisal or measured reaction.

Section 609. Mistake of Law.  Except as otherwise expressly provided, a person's good faith belief that conduct does not constitute a crime is an affirmative defense if he acted in reasonable reliance upon a statement of the law contained in:

     (a) a statute or other enactment;
     (b) a judicial decision, opinion, order or judgment;
     (c) an administrative order or grant of permission; or
     (d) an official interpretation of the public servant or body charged by law with responsibility for the interpretation, administration or enforcement of the law defining the crime.

Section 610. Duress.  (1) Affirmative Defense. In a prosecution for any offense it is an affirmative defense that the actor engaged in the proscribed conduct because he was compelled to do so by threat of imminent death or serious bodily injury to himself or another. In a prosecution for an offense which does not constitute a felony, it is an affirmative defense that the actor engaged in the proscribed conduct because he was compelled to do so by force or threat of force. Compulsion within the meaning of this section exists only if the force, threat or circumstances are such as would render a person of reasonable firmness incapable of resisting the pressure.

(2) Defense Precluded. The defense defined in this section is not available to a person who, by voluntarily entering into a criminal enterprise, or otherwise, willfully placed himself in a situation in which it was foreseeable that he would be subjected to duress. The defense is also unavailable if he was negligent in placing himself in such a situation, whenever negligence suffices to establish culpability for the offense charged.

Section 619. Definitions for Chapter 6.  In this Chapter:

     (a) "force" means physical action, threat or menace against another, and includes confinement;
     (b) "deadly force" means force which a person uses with the intent of causing, or which he knows to create a substantial risk of causing, death or serious bodily injury. Intentionally firing a firearm or hurling a destructive device in the direction of another person or at a moving vehicle in which another person is believed to be constitutes deadly force. A threat to cause death or serious bodily injury, by the production of a weapon or otherwise, so long as the actor’s intent is limited to creating an apprehension that he will use deadly force if necessary, does not constitute deadly force;
     (c) "premises" means all or any part of a building or real property, or any structure, vehicle or watercraft used for overnight lodging of persons, or used by persons for carrying on business therein;
     (d) "dwelling" means any building or structure, though movable or temporary, or a portion thereof, which is for the time being a person's home or place of lodging.