In middle school, Jhovani Becerra witnessed his classmates get suspended for small infractions like mouthing off to teachers or violating the school dress code. The student from Denver, Colorado, thought such a system was perfectly normal.

It wasn't until high school that Becerra, 18, who came to the U.S. from Mexico as a young child, realized it wasn't. In his new school the administration offered emotional support to struggling students instead of a zero-tolerance policy that demanded blanket punishments for even minor infractions....

The changes Becerra experienced are representative of a transformation administrators at Denver Public Schools (DPS) are trying to create for students at all levels in the district. Over the past decade, DPS has emerged as a national leader in its push to end the so-called school-to-prison pipeline, which experts say funnels children into the nation's jails through zero-tolerance policies that criminalize student misbehavior. Zero-tolerance policies can push students out of schools and onto the streets through excessive suspensions. Having cops in schools can also be a factor, because it means police are more likely to intervene in instances of student misbehavior than teachers and administrators.

Through working with a local grassroots group called Padres & Jóvenes Unidos, which translates as "Parents and youth united," the district has taken strides to rewrite its discipline codes. With the help of the organization, the district and the local police department -- which supplies resource officers for schools -- signed an agreement in 2013 that clarified and limited the power of police in schools. As a result, Denver schools have seen a substantial drop in the number of student suspensions and expulsions, according to a report the group released in May. In the 2011-2012 and 2013-2014 school years, in-school suspensions dropped 27 percent, out-of-school suspensions dropped 10 percent and expulsions dropped nine percent.