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I have decided to leave the Minneapolis School District where I have been teaching middle school since 2015.

This has been a difficult decision for me. I live in Minneapolis and all three of my children are in (or have graduated from) Minneapolis schools. In fact, I have taught all of my own children with my youngest currently in my class.

We have been involved with the district as a family since my oldest child was in kindergarten in the 2009-10 school year. I have been a staunch advocate for Minneapolis schools, promoting the district among neighbors and other parents for years.

But I realized this year that I must leave Minneapolis because every day is a constant struggle against cellphone usage.

The deterioration of students' mental health and academic success is tangible over the last two years. We had one year with a strict cellphone policy of "if we see it, it's confiscated." This worked! The number of fights dramatically decreased; students were on time to class and more focused once there.

The truth is, getting kids to behave should not be that difficult. We need to have rules with set expectations and set consequences for those who are more risk-taking and need to test the boundaries. Students cannot thrive under rules that change from classroom to classroom.

Many Minneapolis students come from impoverished backgrounds. Many have experienced traumatic events, and all of them need additional support to be as successful as they can be.

Middle school students' brains are still developing. They need adults to set clear boundaries for them. The U.S. Surgeon General has clearly stated how detrimental social media is for our children. The Atlantic recently published an article about the decline of test scores simply from having a phone present in the room.

As conscientious, caring adults we must create environments that allow our children to thrive, and to learn to interact with each other in person.

Students cannot decide for themselves what is best for their brain development. They need to have no-holds barred guidelines to follow. That is what allows them to feel more secure and to truly be educated.

As a school district, we ought to be liable if a child does not receive an education while are under our supervision.

I have come to the conclusion that I cannot stand by and support a system that does not stand up for the rights of our children by saying "no." No cellphones, no earbuds, no distractions from devices. Parents entrust us to care for their children and we are not holding up our end of the bargain.

I implore our community to stand up for what our children most need — a consistent classroom environment free of external distractions. We must correct the damage that is already done and move forward with providing high expectations for academic learning. This must begin with a ban on cellphone usage and the means to enforce that ban.

Laura Kimball, of Minneapolis, is a middle school science teacher.