Maria Mendez of The Texas Tribune summarizes what has been learned since the massacre of 19 students and two teachers at Robb Elementary School in Uvalde, Texas, one year ago.

What we know for sure: 376 armed officers converged on the school, knowing that a gunman was killing children and teachers inside two conjoined classrooms, where there were 33 children and three teachers.

For 77 minutes, none of the officers entered the classroom to confront the killer. They were afraid of the killer’s AR-15.

What we have learned since: there was a catastrophic breakdown in leadership and communications. No one was sure who was in charge.

Law enforcement across the nation has been trained to confront and neutralize the killer as quickly as possible. When one officer started to enter the killing zone, none of his colleagues backed him up. When a dying teacher called her husband, who was a police officer at the scene, he tried to rush to her aid but he was stopped and disarmed.

In two and a half minutes, before any police officer set foot inside the school, the gunman fired more than 100 rounds at students and teachers from point-blank range. Upon breach, 18 of the 21 victims were already dead.

Had the officers followed standard protocol and entered the classrooms immediately, some of those who were grievously wounded might have survived.

Inside the school, some police officers attempted to approach the classrooms the gunman took over, but they weren’t backed up by colleagues, according to records and footage reviewed by The Texas Tribune.

Another frustrated state trooper urged officers to enter but was told by a police officer that they hadn’t received those orders….

The disjointed medical response, which also included lapses in communication and muddled lines of authority, frustrated medics while delaying efforts to get ambulances, air transport and other emergency services to victims.

For example, medical helicopters with critical supplies of blood tried to land at the school, but an unidentified fire department official told them to wait at an airport 3 miles away. And only two ambulances were seen outside the school in police camera footage, while dozens of parked police vehicles blocked other ambulances’ paths.

What’s happened since: Congress passed a bill introduced by Republican Senator Jon Cornyn of Texas. Texas has spent money on security.

Within weeks of the shooting, federal lawmakers passed the Bipartisan Safer Communities Act. Republican U.S. Sen. John Cornyn helped negotiate passage of the legislation, which contained modest provisions but which was also the most significant federal gun measure passed in nearly three decades. But rather than pass gun measures of their own, state leaders have largely focused on improving school safety and access to mental health care.

Texas Republicans hold a supermajority, and they oppose restrictions on gun ownership.

Abbott and other Texas Republicans have mostly ignored calls for increased gun restrictions since the Uvalde shooting, instead focusing on mental health funding and school safety.

In late June, Abbott and state leaders announced they would dedicate $100 million in state funds to boost school safety and mental health services through August 2023. Most of the funds went toward bullet-resistant shields for school police officers and for school districts to buy silent panic alert technology to alert police of an intruder.

Cornyn negotiated a federal bill signed into law last June with modest gun control measures that addressed a “boyfriend loophole,” which previously exempted some dating partners from a federal ban on firearm purchases for those convicted of domestic violence. The bill also included incentives for states to impose “red flag laws,” which allow for the temporary confiscation of guns from people found by a judge to be dangerous. Texas has not moved to impose such a law.

Texas lawmakers also appear unlikely to raise the minimum age to buy semi-automatic rifles like the AR-15 from 18 to 21 after a bill to do so missed key legislative deadlines. But gun safety advocates say they still see incremental progress through two gun-related bills passed by both chambers of the Legislature.

Senate Bill 728 requires courts to report involuntary mental health hospitalizations of juveniles 16 and older for inclusion in the federal background check system to purchase firearms. The bill, sent to the governor’s desk, addresses a loophole exposed by The Texas Tribune and ProPublica following the shooting in Uvalde.

House Bill 2454 would restrict a person from buying a gun for another person not allowed to have one. It has passed both chambers, but the House must accept or negotiate amendments made to the bill by the Senate before the legislative session ends May 29.

Lawmakers have also advanced legislation to fund campus security upgrades, add requirements such as silent panic buttons in classrooms and create a new safety and security department within the Texas Education Agency. The department would have the authority to compel school districts to establish active-shooter protocols — something about half of the state’s school districts failed to have, according to an audit in 2020.

None of these changes at the state and federal levels would have prevented the Uvalde massacre. Children and teachers called 911, as they lay dying. Would a silent panic button have given the officers the nerve to enter the classroom sooner? Would the killer have signed up for mental health services?