Montana has a Castle Doctrine as a defense to a murder charge.  However, it is currently being reexamined.  Heather Fredenberg had an affair with Brice Harper. Her husband, Dan Fredenberg, found out about the affair and went to Mr. Harper’s house to confront him.  Mr. Fredenburg walked though a open garage door where he was shot and killed.

Prosecutors declined to press charges stating Harper was protected by Montana’s Castle Doctrine law.  Harper believed he was about to be assaulted; therefore, his use of force was justified under the law even though Fredenberg was unarmed.

County Attorney Ed Corrigan, in a letter (PDF) to members of the Kalispell Police Department, outlined his reasoning for not pressing charges against Brice Harper.  Mr. Corrigan relied on Montana’s version of the Castle Doctrine, a prior altercation between the parties and Mr. Harper’s statements at the time of the killing.  The biggest issue was that that Mr. Fredenberg, who again was unarmed, was shot three times.

Here is Tennessee’s version of the Castle Doctrine:

 Notwithstanding § 39-17-1322, a person who is not engaged in unlawful activity and is in a place where the person has a right to be, has no duty to retreat before threatening or using force intended or likely to cause death or serious bodily injury, if:

    (A) The person has a reasonable belief that there is an imminent danger of death or serious bodily injury;

   (B) The danger creating the belief of imminent death or serious bodily injury is real, or honestly believed to be real at the time; and

    (C) The belief of danger is founded upon reasonable grounds.

(c) Any person using force intended or likely to cause death or serious bodily injury within a residence, business, dwelling or vehicle is presumed to have held a reasonable belief of imminent death or serious bodily injury to self, family, a member of the household or a person visiting as an invited guest, when that force is used against another person, who unlawfully and forcibly enters or has unlawfully and forcibly entered the residence, business, dwelling or vehicle, and the person using defensive force knew or had reason to believe that an unlawful and forcible entry occurred.

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The basic principle is that a man’s home is his castle. He can protect his family or himself while at home. The defense is very similar to the defense being used in Florida in the Zimmerman case.
 
The question posed is should it be a defense to kill someone at your home under certain circumstances ?