This is a question originally asked on Quora. I decided to cross post my answer to the Steem blockchain to establish its originality in case I wish to republish it later. And also because why not? So without further adieu here is my answer to:
Can I shoot a thief from my dad's license[d] gun if he tries to rob my house at night time?
[Note ― I have used my lawfully carried firearm in self defense more than once. In each case I was fully prepared to live with the outcome. I am glad that no one died. However, given the same circumstances I would make the same choices, knowing full well the consequences could have been much worse.]
Courtesy Sofia Sforza on Unsplash
I will address the question from the standpoint of legal justification as applied in the states where I live. Questions of morality, psychology and physical means do not seem to be what OP is driving at.
Generally speaking a person has a strong claim to justified use of force within their own dwelling place, against people who otherwise have no right to be there, and who mean to do harm.
Here you have posited that a thief has burgled a dwelling at night. There are few jurisdictions that fail to view these facts as justification for the use of deadly force. The reason for this is that the invasion of an occupied home (burglary) leads to a strong presumption that the burglar poses a threat.
In other words, society has decided not to put the victim of a burglary in the precarious position of having to discern whether a burglar is there to attack or merely to trespass and steal―the violation of a home is enough to show that the intruder is dangerous.
Some jurisdictions make this explicit. In Florida, for example, the relevant portions of F.S. 776.013 provides:
A person who is in a dwelling or residence in which the person has a right to be has no duty to retreat and has the right to stand his or her ground and use or threaten to use…deadly force if he or she reasonably believes [it] is necessary to prevent imminent death or great bodily harm to himself or herself or another or to prevent the imminent commission of a forcible felony.
The same law further details that a person is presumed to have a reasonable fear of imminent death or severe harm if an intruder unlawfully and forcefully enters a dwelling, residence, or occupied vehicle.
While the specifics do vary ,this approach is followed in principle by most states. Notable exceptions do include Vermont and the District of Columbia. Nevertheless, even in those jurisdictions that do not codify a presumption one still has what might be called the “ordinary” right to self defense.
Under this standard lethal force is still justified to prevent death, grievous harm and felonies. The difference would be that the home invasion becomes a factor in a question of fact. Was there a sufficient threat to justify the shooting? I expect most courts and juries would give this factor tremendous weight―and prosecutors and police expect it to.
You’ll notice that up until now I have not spent any time discussing the “from my dad's license[d] gun” aspect of the question as posed.
That’s because it’s not very important how one comes to possess a gun while it is necessary for self-defense. Self-defense is a special case of the general defense of justification.
In jurisprudence, justification means that someone actually committed a crime. But the perpetrator is not guilty because committing the crime advanced the general welfare of the community or vindicated a right of such magnitude that it outweighs the wrongfulness of the crime.
The crime could be a homicide or assault with a deadly weapon. This is the case with typical self-defense. But the crime could also be unlawful possession of a firearm or something as common as speeding. True story―I once successfully argued justification on a parking ticket and won.
The point being that where self-defense can be established it’s very likely any less serious crimes committed in the same defense of life and limb are justifiable as well.
So, to sum up. I’d have no doubt about defending myself with lethal force in the circumstances described. Every life is precious. The lives for which we bear the most responsibility are our own and the lives of those we love.