These distinctions might not seem like they matter much. But partly because of these fundamental misunderstandings, nationwide efforts to stamp out bullying intensified after Columbine. At the same time, zero tolerance policies—already growing more prevalent in the years immediately prior to Columbine, thanks in part to the 1994 Gun Free Schools Act—became even more popular, giving schools all sorts of means for expelling problematic, “bullying” kids. It’s no wonder that by 2006 the school suspension rate was double what it had been in the 1970s. These trends were already underway before Columbine, but the massacre made them seem more necessary and intensified the push for them.

Schools also continued to employ more and more school resource officers to police hallways and classrooms. The federal Community Oriented Police Services office doled out hundreds of millions of dollars from 1999 to 2005 so that schools could hire cops. Columbine is not solely responsible for this, but the public’s massive, sudden post-Columbine terror about violence in schools ensured that SROs and zero tolerance remained popular. This terror was largely unjustified, given that school violence—like most kinds of violence—was falling over this time period. But these policies were anything but harmless: Students have increasingly had to endure prison-like conditions.

Ignorance about the relatively low likelihood of school shootings is just as widespread today.