Almost two months ago, gunfire erupted at Marjory Stoneman Douglas High School in Parkland, Florida, killing 17 and injuring another 17. One of those wounded, 15-year-old Anthony Borges, was shot five times as he barricaded his classroom door with his body.

On April 4, Mr. Borges was released from hospital — the last Parkland victim to return home. That same day, Education Secretary Betsy DeVos convened two “listening sessions” with educators, students, and leaders of national organizations concerned with improving public-school safety.

It wasn’t Mrs. DeVos’ first dive into the issue. Last fall, she met with school officials to discuss federal school discipline guidance. The Parkland tragedy has given this review new urgency.

Of particular interest is a “Dear Colleague” letter issued by the Obama administration in 2014. This guidance from the Department of Education and the Department of Justice instructed school officials to “administer student discipline without discriminating on the basis of race, color, or national origin.”

Obviously, individuals should not be suspended or expelled from school just because of the color of their skin. But the letter was more than a simple warning on discrimination.

It also gave recommendations for how schools should discipline students without resorting to suspensions, expulsions, or law enforcement involvement (“exclusionary discipline”). And according to reports, dozens of school systems have adjusted their discipline policies accordingly.

This federal guidance resembles Broward County’s school discipline policies, called PROMISE, or Preventing Recidivism through Opportunities, Mentoring, Interventions, Supports, and Education. Broward officials announced PROMISE with much fanfare in 2013 — two months before the federal guidance.

These discipline policies are the intersection between Parkland and the federal letter. In 2014, Broward Superintendent Robert Runcie said, “The Obama administration might have taken our policies and framework and developed them into national guidelines.” The Obama administration featured Broward County at a 2015 White House event on school discipline.

PROMISE is committed to “significantly [reducing] the practice of linking inappropriate behavior with a referral to law enforcement,” while the federal guidance says schools should “utilize exclusionary disciplinary sanctions as a last resort.”

The documents also encourage “restorative justice” and ask students to resolve an issue so that school officials and law enforcement do not have to use exclusionary discipline.

Asking students to work things out without calling the cops is noble, but now families and policymakers are asking whether adults did enough to prevent a troubled student from harming others at Stoneman Douglas.

Shooting suspect Nikolas Cruz appears to have done at least two things that should have resulted in referral to PROMISE well before the shooting. According to reports, Mr. Cruz publicly threatened to “shoot up” the school. He also committed assault while attending Douglas.

Both threats and assault are listed as PROMISE-eligible actions. Yet he was never referred to PROMISE or arrested (Mr. Cruz also committed more than two dozen other infractions, both in and out of school).

It certainly appears as though school safety measures that mirror the Obama administration’s federal guidance failed — over the course of several years — to effectively deal with a troubled student. If PROMISE is based on “the most comprehensive thinking available to address socially unacceptable or illegal behavior,” then why wasn’t Mr. Cruz stopped before the shooting?

A Sunshine State News report said, “It will be up to Broward County School Board members and other officials to determine what role the PROMISE program played in the Parkland tragedy, and whether schools are more dangerous because of it.” But some families aren’t waiting. CNN reports that the family of teen-hero Mr. Borges is planning to sue Broward County schools and law enforcement.

Washington is too far removed from neighborhood schools to issue and enforce guidance on school discipline across 50 states and 50 million students. As Broward families’ grief turns from anger and pain to hard questions about what went wrong, Washington should rescind its school discipline directives at the center of the tragedy.