A coalition of advocacy groups including the NAACP Legal Defense Fund is pushing back against the idea of upping the number of armed police officers in schools, a suggestion being considered by the White House in the wake of the Newtown, Conn., shooting tragedy.

The groups – which include the Advancement Project, the Dignity in Schools Campaign and the Alliance for Educational Justice – released an issue brief Friday in which they warn of the “unintended consequences” of a greater police presence in schools, such as increased criminalization of students.