A white man in Kansas City is accused of shooting a Black teenager who rang his doorbell by mistake, renewing attention on Missouri’s self-defense laws after the man, Andrew Lester, 84, said he shot Ralph Yarl, 16, because he feared for his safety.

Lester has since been charged with two felonies and said he was “scared to death” when the teen showed up at his front door. Yarl, who has been described by a family friend as quiet and respectful, was trying to pick up his siblings from a friend’s house and went to the wrong address. The shooting, which the prosecutor acknowledged had a racial component, has sparked protests calling for strong action against Lester.

Self-defense laws known as “stand your ground” statutes and “castle doctrine” – are part of many of states’ legal frameworks and have increasingly been part of the debate over gun violence. Here’s what you need to know.

What is ‘stand your ground,’ and how is it relevant in the Ralph Yarl shooting?

“Stand your ground” laws say that when a person perceives a threat in a place where they have a right to be (i.e. public spaces), they are permitted to respond immediately with physical, even lethal force. The first stand-your-ground law passed in Florida in 2005. Before that, people in the state had a responsibility to attempt to retreat from a conflict before using deadly force, according to the Brady Center to Prevent Gun Violence.

Stand-your-ground laws “minimize criminal penalties and eliminate civil liabilities’ for those who claim self defense in deadly encounters,” researchers at the University of Missouri and Rutgers University wrote in a September 2022 academic paper. By removing the “duty to retreat” from an attacker in public spaces, the laws expand on the “castle doctrine,” which removes the obligation to retreat from an intruder in one’s home.

Conservative groups including the National Rifle Association have touted such statutes as an expansion of self-defense. But opponents of the laws say they increase violence and allow deadly force to become a first instinct, rather than a last resort. According to a 2022 study, stand-your-ground laws are associated with an 11% increase in monthly firearm homicide rates. The Brady Center has said such laws are “made more lethal by our nation’s history of racism.”

Lester, the homeowner, said that he shot Yarl because he believed he “was protecting himself from a physical confrontation” and that he heard Yarl pulling on the storm door, the criminal complaint says, setting up a potential defense that relies on Missouri’s self-defense laws. According to Yarl’s statement, he rang the doorbell and waited quietly for a few minutes before Lester opened the door and fired on him.

What does Missouri’s ‘castle doctrine’ say?

Missouri’s self-defense law states that a person may use physical, deadly force against another person if he or she “reasonably believes that such deadly force is necessary” to protect “against death, serious physical injury, or any forcible felony.”

This applies in a variety of settings, including a dwelling, residence or vehicle where the person is lawfully present; private property owned or leased by the person; and “any other location such person has the right to be,” such as public places.

The “castle doctrine” is the portion of the law that allows such action in one’s home, while stand-your-ground law allows immediate use of force in other locations. Missouri does not have explicit “stand your ground” language written into its law; some states, including Florida, Alabama and Georgia, do.

Because the events took place at Lester’s home, the castle doctrine is particularly relevant in this case, though lawyers told The Washington Post that ringing a doorbell is not a justifiable reason for using deadly force.

“You have to do more than just say, ‘I felt threatened’; you have to prove that something threatening was going on,” Daniel Webster, a professor at Johns Hopkins University’s Center for Gun Violence Prevention and Policy, said.

What states have stand-your-ground laws, and how have they been used?

At least 28 states and Puerto Rico have these laws, according to the National Conference of State Legislatures.

One such Florida law was said to play a role in the acquittal of George Zimmerman, who fatally shot 17-year-old Trayvon Martin while the teenager was walking back from 7-Eleven in 2012. While Zimmerman’s lawyers did not cite “stand your ground” in the defense, the jury that acquitted him received instructions about the law.

When Texas Gov. Greg Abbott (R) said he was working on pardoning Daniel Perry – who was convicted this month of killing Garrett Foster while Foster, who was lawfully carrying a rifle, was protesting at a Black Lives Matter rally in 2020 – Abbott noted: “Texas has one of the strongest ‘Stand Your Ground’ laws of self-defense.”