“I don’t want to be scared. I don’t want to think that at any moment someone with a gun could walk in and hurt us all,” Ms. Modjarrad said. “Please consider the possibilities that guns are the most important aspect of the purview of this commission.”

The speakers’ demands largely echoed the responses that liberal advocacy groups have pointed to since the Feb. 14 massacre at Marjory Stoneman Douglas High School: more anti-violence programs, more mental health resources and better coordination between school and law enforcement officials in trying to identify at-risk students.

But the hearing provided a platform for voices from outside Washington who have dealt directly with violence inside and outside school buildings. They offered insight into the most divisive issues facing the commission: guns and the increased presence of law enforcement in schools.

Advocates and educators have worried that the Trump administration’s push toward “hardening schools” with weapons and law enforcement officers will worsen outcomes for minority students, who already are arrested at school at higher rates than their white peers. According to the Education Department’s most recent civil rights data, black students were 15 percent of all students in the 2015-16 school year but accounted for 31 percent of arrests or referrals to police, a disparity that had widened by five percentage points since 2013-14.

Amina Henderson-Redwan, a 20-year-old with Voices of Youth in Chicago Education, urged the commission to keep students like her in mind. She has struggled with mental illness, was arrested at school after having an anxiety attack and had her head pushed into a chalkboard by a security guard. She lost her best friend to gun violence in February.