"I don't think our kids need to be treated like criminals," said Duchow.

Duchow and Johnson said requiring students to provide a urine sample in front of school staff or law enforcement could be traumatizing. "To watch a child — a child— urinate into a cup is trading one form of trauma for another," Johnson said.

Schools police themselves

Duchow said it's not difficult to figure out who is selling and taking controlled substances and that schools already do a good job of policing themselves without additional regulations from state lawmakers.

"I do not like to mandate anything to our schools," Duchow said. "Another mandate — and another unfunded mandate — I don't think they need."

Susan Opper, Waukesha County district attorney, said the legislation targets students who are under the influence and "it's virtually impossible to tell."

"It's the ones that nobody — the parents, the teachers — nobody has a clue what they're up to," Opper said. "I've met too many families and too many parents who say I wish I would have known and drug testing is the way to know."