Four plaintiffs filed an appeal Thursday in their fight to challenge Minnesota's teacher tenure laws.

A judge rejected their suit in October but the parents are back to assert that state laws are protecting ineffective teachers and violating students' rights by keeping low-income and minority students from attaining a quality education.

"This lawsuit is about our children, said Roxanne Draughn, mother from St. Paul and a plaintiff in the case, said in a statement. "And when your child is suffering, as a parent you can't back down."

Judge Margaret Marrinan dismissed the suit, filed last Apri on the grounds that no link could be made between academic achievement and due process for teacher tenure laws.

In their appeal, the plaintiffs argue that the state has created a barrier by keeping students from their constitutional right to an adequate education. They indicate that the state has defined its measures on teacher effectiveness to ensure that students receive a quality education.

"It is the courts' role to ensure that laws do not violate constitutional rights," Jesse Stewart, attorney representing the plaintiffs, said in a statement.

Education Minnesota released a statement in January when the plaintiffs filed their notice of appeal. In the statement, the teacher's union expressed that the appeal was another attempt to silence teachers.

"Due process protections are earned by Minnesota teachers after they have passed a lengthy probationary period and have met certain performance expectations," Education Minnesota President Denise Specht said. "These laws don't prevent bad teachers from getting fired. They prevent good teachers from being fired for bad reasons."