Two years ago, 17 people died in a mass shooting at Marjory Stoneman Douglas High School, in Parkland, Fla. In the intervening years, both those who survived it and those who observed it from afar have tried to figure out how something so terrible could have happened.That is understandable. Unfortunately, the tone of public debate on this matter was set early, and unhelpfully, on just one subject: gun control. The morning after the shooting, Parkland school superintendent Robert Runcie said that “now is the time to have a real conversation about gun control laws in our country.” Just a few days later, Broward County sheriff Scott Israel said: “While the people who are victims of mental-health illnesses in this country are being treated, in the opinion of this sheriff, they should not be able to buy, surround themselves with, purchase or carry a handgun. Those two things don’t mix.” David Hogg, a Stoneman student at school on that evil day, demanded national action on gun control shortly after as well. “We are children. You guys are, like, the adults,” he said. “Take action, work together, come over your politics, and get something done.” Hogg then helped spearhead a mass political rally in Washington, D.C., the next month, the “March For Our Lives,” that again emphasized this call for federal action on gun control.Those who survived something as horrendous as the Parkland shooting do not deserve unnecessary opprobrium. But the fact remains that it was not Senate majority leader Mitch McConnell, President Donald Trump, or the National Rifle Association who were responsible for the murder of 17 people on that February day. It was a depressing cascade of actions (and inactions) by local actors over a series of years, and even on the day of the shooting, that sealed the victims’ fate. The collective failure to recognize and accept this, even years later, may be a consequence of a political culture that insists on all problems’ being made national. In any case, it simultaneously does nothing for the victims of Parkland and does little to prevent future similar slaughters.This story turns, sadly, on the shooter himself. (As recent research has suggested that media coverage of mass shootings can inspire subsequent ones, it is best not to use his name.)The shooter displayed violent tendencies from a young age, and through multiple schools, all the way up to the day he killed those 17 people. As a young child raised mostly by an adoptive single mother, he often fought with neighborhood children. He tortured animals. He argued frequently with his own family, quickly escalating verbal confrontations to physical ones. At one point, he required a physical harness to ride the school bus without attacking other students. Throughout his grade-school and middle-school years, he physically and verbally assaulted students and bragged about his mutilations of animals. He attempted to commit suicide during a fire drill. When transferred to a school for students with special needs, he openly obsessed over guns and violence, at one point bringing a weapon to the school. He continued virtually all of these behaviors as he matriculated into Marjory Stoneman Douglas High School, getting into several fights, sending death threats to ex-girlfriends and others, openly proclaiming his desire to shoot up the school to anyone who would listen, dressing in full camouflage gear, bringing dead animals to class, and, once again, bringing weapons (knives and bullet casings) to school grounds. All of this happened before February 14, 2018; he was seriously punished for surprisingly little of it.Could hindsight be 20/20? After the fact, many of these school shootings seem obvious, and their perpetrators fit a similar pattern: young, isolated, troubled, aggrieved, male. But it is impossible to overlook the sheer number of times somebody actively warned about the Parkland shooter’s tendencies only to be ignored.Florida mental-health officials declined on multiple separate occasions to institutionalize him. On February 5, 2016, the shooter posted a picture of himself posing with a gun to his Instagram account with the caption: “I am going to get this gun and shoot up the school.” A woman alerted a Broward County sheriff about this; he said there was nothing he could do. There were literally dozens of police visits to his house over the years. After he entered Marjory Stoneman Douglas, something his therapist advised against, school staff held a meeting in which they pegged him as the likeliest school shooter among their student body. Eventually, he was forbidden from bringing a backpack to school. When ultimately forced out of the school for academic reasons, he trespassed on school grounds on the first day of the 2017–18 academic year. A YouTube account in his actual name commented on a video that he wanted to become a professional school shooter; the video’s uploader contacted the FBI, which did nothing. Another woman, a family friend, alerted both the Broward County sheriff’s office and the FBI about the shooter’s consistently violent Instagram posts; neither acted on the tip. And a former Secret Service agent warned Parkland officials of the likelihood of a mass shooting given their security protocols.Little, if anything, was done. Demonstrating a horrifying and ultimately damning passivity, a series of ostensibly responsible adults passed up every chance to thwart an increasingly obvious imminent evil.But the failures of those in charge at and around Marjory Stoneman Douglas did not end in the lead-up to the shooting itself. On the very day, their actions enabled, prolonged, and worsened the massacre. The shooter walked right onto school grounds through a gate that security protocols said ought to have been closed. When he got there, campus-security monitor Andrew Medina saw him, recognized him, and knew he no longer belonged at the school. He declined to initiate school security procedures, as Ty Thompson, the principal, had reserved that authority for himself but was away from campus. Medina radioed David Taylor, another campus-security monitor, who went into the building where the shooter had entered, then hid in a closet when he began hearing gunshots, also without initiating security procedures. Meanwhile, school resource officer Scot Peterson, the only other armed person on school grounds, had been informed of gunfire in the school — yet stood idly outside of the affected building for almost an hour, awaiting the arrival of Broward sheriff deputies. They too did little but wait outside the building. And finally, due to miscommunication, Jan Jordan, the captain of the Parkland district of the Broward sheriff’s office, thought that recorded security footage of the shooter was live and delayed allowing both deputies and medics into the building until it was “empty” (on the basis of out-of-date information).By the time officers entered the building, the perpetrator had already fled school grounds with evacuating students. It was a shocking display of incompetence, inaction, and indecision that allowed the Parkland shooting to become what it did. (This is not even an exhaustive account; read the book by education-policy writer Max Eden and father of Parkland victim Andrew Pollack, Why Meadow Died: The People and the Policies That Created the Parkland Shooter and Endanger America’s Students for more.)Seen in this light, the after-the-fact statements by Runcie, Israel, and others blaming the lack of gun control seem more like deflection than any genuine attempt to figure out what happened that day. For they would have to blame themselves, not pat themselves on the back for their “amazing leadership,” to get to the bottom of the events that unfolded. The proximate causes of the tragedy were choices various local actors made — or, in most cases, did not make. They, not some far-off villain with only marginal influence on their day-to-day lives, deserve to be held responsible. As Pollack puts it in Why Meadow Died, “Parkland was the most avoidable mass shooting in American history.”As for Hogg and those like him, it is unfortunate that they followed the lead of these deflecting adults in seeking blame afar. They still have every right to be angry. But the proper target of ire ought to be the officials and policies that directly failed him and all the rest at Stoneman Douglas that day, those who lived and those who died. On the second anniversary of Parkland, let us hope that we can think clearly about the best way to stop anything like it from happening again.