What Are ‘Stand Your Ground’ Laws, and When Do They Apply?

The shooting of a teenager in Kansas City, Mo., and the killing of a woman in upstate New York in recent days have brought renewed attention to the legal protections offered to people who say they acted in self-defense or out of fear for their safety.

In Kansas City, a Black teenager was shot last Thursday when he mistakenly went to the wrong house to pick up his younger brothers. The 84-year-old white man who shot the teenager through his front door has been charged with first-degree assault; he told investigators that he thought someone was breaking into his house.

In New York, a 20-year-old woman looking for a friend’s house was fatally shot on Monday after the car in which she was riding went to the wrong address. The homeowner there fired shots and killed her, the authorities say; he has been charged with second-degree murder.

Missouri is one of about 30 states with a “stand your ground” law. New York is not, but defendants there and elsewhere can argue that their actions are protected by what is known as the “castle doctrine.”

Here is a guide to understanding those laws and legal principles.

What are ‘stand your ground’ laws?

In the United States, there has been a tendency over the years for legislatures and the courts to expand the right to claim self-defense to justify use of force, rather than to protect those who may be harmed by misjudgments and mistakes.

The common-law “castle doctrine,” established through centuries of precedent, is rooted in the idea that a person’s home is their castle, and that they have a right to protect themselves while they are in it.

Castle doctrine laws — sometimes known as “make my day” laws — give people in their own homes the legal presumption of self-defense if they harm an intruder.

“Stand your ground” laws go further. They apply anyplace where a person has a legal right to be, not just at home, and they erode the longstanding “duty to retreat,” a mainstay of classic self-defense legal theory that says deadly force is justified only as a last resort, when retreat is impossible.

For example, Florida’s law states that “a person who is not engaged in an unlawful activity and who is attacked in any other place where he or she has a right to be has no duty to retreat and has the right to stand his or her ground and meet force with force, including deadly force, if he or she reasonably believes it is necessary to do so to prevent death or great bodily harm to himself or herself or another or to prevent the commission of a forcible felony.”

That law gained wider attention in 2012, when the police in Sanford, Fla., cited it as the reason they declined to arrest George Zimmerman, a neighborhood watch volunteer who killed an unarmed Black teenager, Trayvon Martin. Mr. Zimmerman was later charged and acquitted.

Missouri, Florida, Texas, Georgia, Michigan and Pennsylvania are among the states with “stand your ground” laws, according to the National Conference of State Legislatures. Most such laws have been enacted in the last 25 years.

How might the laws apply in the Missouri and New York cases?

The prosecutor in Kansas City has said that he believes the shooting of the teenager, Ralph Yarl, 16, was not in self-defense.

S. David Mitchell, a law professor at the University of Missouri, said that a defense lawyer could try to invoke the castle doctrine, though it usually applies only when an intruder has entered the home. The front porch, Mr. Mitchell said, “becomes the gray area of what constitutes one’s castle,” a question that a jury could consider.

Though “stand your ground” laws do not require a person to retreat, they do not provide a blanket defense for shooting at anyone who approaches you. Mr. Mitchell said there would also have to be an assessment of whether the shooter had a “reasonable fear” of being harmed.

“There’s one key thing that is missing here,” he said, referring to the shooting in Kansas City. “There is no indication of reasonable fear that I’ve seen from any of the reports.”

Under New York’s castle doctrine, people have a right to protect their homes with deadly force if they reasonably believe that someone is entering without permission and is seeking to commit a crime.

But the sheriff in Washington County, where the wrong-address shooting took place on Monday, said he believed there was no reason for the suspect, Kevin Monahan, 65, to have felt threatened when he stepped out of his house and killed Kaylin Gillis, 20.

Why do states say they need ‘stand your ground’ laws?

Proponents argue that the laws allow citizens to keep themselves safe, and even that the laws deter crime, though there is no evidence of that.

Missouri was the first state to pass a “stand your ground” law after the killing of Trayvon Martin in Florida.

The Republican-controlled Missouri General Assembly overrode the veto of Gov. Jay Nixon, a Democrat, in 2016 to approve the legislation, which allows individuals to use force in self-defense without retreating in any location where they have the right to be. Instead of providing the right only in the home, the law created a sort of mobile self-protective bubble, said Mr. Mitchell, the law professor.

The bill was sponsored by Sen. Kurt Schaefer, a Republican from Columbia, Mo. “You’re going to do whatever you need to do if your safety is in jeopardy,” Mr. Schaefer said in 2016. “The question is, what happens in the lawsuit after that? Are you going to be faced with liability after that?”

What do opponents of the laws say?

Critics say the laws make it too easy to claim self-defense when violence could have been avoided. For criminal trials in which a defendant claims self-defense, the law puts the burden on prosecutors to try to discredit those claims.

According to some analyses, there are substantial racial disparities in rulings of justifiable homicide under the laws.

Opponents also say the laws promote violence and weaken police powers. There is moderate evidence that the laws may increase total homicide rates, according to a review of data by the RAND Corporation.

What are some noted cases in which defendants have argued they acted in self-defense?

The 2013 trial and acquittal of George Zimmerman put “stand your ground” laws in the national spotlight. In finding him not guilty of murder or manslaughter, the trial jury agreed that Mr. Zimmerman could have been justified in shooting Mr. Martin because he feared great bodily harm or death.

In 2021, Kyle Rittenhouse claimed that he had acted in self-defense when he shot three men, killing two, during unrest following the police shooting of a Black man in Kenosha, Wis., in August 2020. The onus was on the prosecution to prove otherwise, and he was found not guilty. That case highlighted for many Americans the wide berth given to defendants who say they have acted out of fear.

This month in Texas, Gov. Greg Abbott said that he would grant a pardon to an Army sergeant who was convicted of fatally shooting a protester during a Black Lives Matter demonstration in 2020. Mr. Abbott, a Republican, cited the state’s strong “stand your ground” law as the basis for his decision.