How mass shootings have historically prompted changes in gun laws

Recent mass shootings have put a spotlight on the gun laws of the states in which these tragedies happened and the actions that local legislators take to address the growing impact of gun violence on the U.S.

Maine has come under scrutiny for its lack of gun restrictions following the Oct. 25 shooting in Lewiston, Maine, that left 18 people dead and injured 13 more.

The state, despite having Democratic control of the legislature and the governor's seat, has failed to push stronger gun laws. Some Maine legislators have since begun promising stronger measures to curb gun violence following the tragedy.

ABC News took a look at several states that experienced some of the deadliest shootings in the U.S. and what laws were implemented following the respective shootings.

Florida

Florida has experienced several major mass shootings in recent years. In June 2016, a gunman opened fire in an LGBTQ nightclub in Orlando. Forty-nine people were killed and dozens more were injured.

In 2018, Marjory Stoneman Douglas High School in Parkland became the site of a mass shooting in which 17 people were killed and 17 others were injured.

Following the 2018 shooting, Florida enacted an Extreme Risk Protection Order law to enable law enforcement to petition a court "to temporarily prevent individuals who are at high risk of harming themselves or others from accessing firearms or ammunition."

"Every student in Florida has a right to learn in a safe environment and every parent has the right to send their kids to school knowing that they will return safely at the end of the day," said then-Gov. Rick Scott before signing the bill.

Lawmakers also raised the minimum age to purchase a gun to 21 and turned the ownership of bump stocks, which could make a semiautomatic rifle fire more rapidly, into a felony.

However, in more recent years, some legislators have worked to weaken gun laws in the state, including eliminating the requirement of a permit for concealed carry.

Nevada

In 2017, 58 people were killed and hundreds injured after a gunman opened fire from the 32nd floor of the Mandalay Bay Resort and Casino in Las Vegas, Nevada. Two victims would later succumb to injuries in the years following the massacre.

Since then, the state has enacted gun safety policies including universal background checks, an Extreme Risk law similar to Florida's, and requiring that guns be stored safely away from children.

"This past session, Nevadans stood together and took bold action to try and prevent these tragedies in the future," then-Gov. Steve Sisolak said in a 2019 press conference at the time after signing the bill.

Legislators also banned bump stocks, which had been used in the 2017 shooting. However, the law is being challenged in court.

Several recent gun restriction efforts in Nevada have faltered.

Gov. Joe Lombardo has vetoed three bills -- one would have restricted the purchase, possession or ownership of a firearm by a person who committed or attempted to commit a crime motivated by bias.

The other two would have prohibited the possession of firearms under certain circumstances, like near polling places, and would have barred people under the age of 21 from possessing certain firearms, including semiautomatic shotguns and assault weapons.

"I will not support legislation that infringes on the constitutional rights of Nevadans," Lombardo said in a May online statement at the time. "Much of the legislation I vetoed today is in direct conflict with legal precedent and established constitutional protections. Therefore, I cannot support them."

Texas

In May 2022, 19 children and two teachers were killed when a gunman opened fire with an AR-15-style rifle at Robb Elementary School in Uvalde, Texas.

Anti-gun violence activists and those affected by the shooting have had little success in changing gun laws in the state following the tragedy.

Families of the victims fought to pass a raise-the-age law that would have raised the age to buy assault rifle-style weapons from 18 to 21. However, legislative leaders in the state were against the measure, including Gov. Greg Abbott who called it "unconstitutional."

However, lawmakers have passed a law to require counties to send information on juvenile mental health cases for review for the National Instant Criminal Background Check System. The Uvalde shooter was 18.

New York

After 10 people, all African American, were killed in a racially motivated mass shooting at a supermarket in Buffalo, New York, in May 2022, Gov. Kathy Hochul signed a ten-bill package of laws to address gun violence in the state.

"Gun violence is an epidemic that is tearing our country apart," said Hochul in a statement on the signing. "Thoughts and prayers won't fix this, but taking strong action will."

The legislation included limiting the purchase of body armor to only specific professions and restrictions on the purchase of semiautomatic rifles to people over 21, strengthening red flag laws, enhancing reporting by law enforcement to the state and federal gun databases and closing "loopholes" in gun law.

Because of the racial nature of the crime, legislators also included new requirements on social media networks to provide policies to respond to hateful conduct on their platform. The legislation also created a task force to investigate the role of social media in facilitating extremism and terrorism online.

Colorado

A mass shooting at a Colorado Springs LGBTQ bar called Club Q killed five people and left over a dozen injured in November 2022, reopening wounds from the Columbine High School shooting in 1999.

Following the shooting, Gov. Jared Polis signed several gun restriction measures.

"Today we are taking some important steps to help make Colorado one of the ten safest states, and building upon the ongoing work to make Colorado communities safer," said Polis in a statement on the signing.

This includes raising the purchasing age for all guns to 21, establishing a three-day waiting period between when people purchase a gun and when they receive it, and strengthening the state's red flag laws that allow guns to be temporarily removed from a person who poses a risk to themselves or others.

Another law enhances gun violence victims' ability to sue the firearms industry.