There's a poll on this page about whether homeowners should be able to defend themselves with deadly force:
http://www.nbc4.com/news/2947451/detail.html
http://www.nbc4.com/news/2947451/detail.html
FOR the purpose of establishing that a certain person who uses deadly force or force likely to cause death in the person's business establishment is presumed to have held a reasonable fear of imminent peril of death or serious physical injury to the person or an employee of the person's business establishment, if force is used against another who enters or has entered the person's business establishment unlawfully and forcibly; providing that a person is not civilly liable for any act arising from the use of deadly force or force likely to cause death in protecting or attempting to protect the person or an employee of the person's business establishment; providing that certain provisions of this Act apply to an owner, lessor, or supervisory employee of a business establishment; establishing that a person who uses deadly force or force likely to cause death in the person's residence is presumed to have held a reasonable fear of imminent peril of death or serious physical injury to the person or a member of the person's family or household, if the force is used against another who enters or has entered the person's residence unlawfully and forcibly; providing that a person is not civilly liable for any act arising from the use of deadly force or force likely to cause death in protecting or attempting to protect the person or a member of the person's family or household; defining a certain term; providing for the application of this Act; and generally relating to the use of deadly force in a business establishment or residence.
I can't speak for everyone else, but for me that isn't what I advocate.. The homeowner may not kill a trespasser simply for being on the property, and may not kill to protect property alone (e.g., kill a person stealing a vehicle from the driveway).
In your home that is true, MD does have the "Castle Doctrine", however outside of your home in MD you are obligated to try to run or otherwise escape before meeting deadly force with deadly force. That escape attempt, or time lost looking for an out, can be the difference between life and death. That is one of many laws that I was talking about needing changed here.If the trespasser or the car thief presents a weapon, then the homeowner is justified in using deadly force to protect himself, but that is not protection of property.