One of the most powerful law-and-order forces in Portland politics has broken rank with President Donald Trump and the National Rifle Association in the aftermath of the shooting at a Parkland, Florida high school that killed 17 people.

The Portland police union has publicly rebuked the president's suggestion to arm teachers in order to prevent future mass shootings.

"Without the proper training, the outcome could be disastrous," Portland Police Association president Daryl Turner said in a press release Wednesday. "A teacher's job is to educate children and it would be hard for the vast majority to quickly become highly skilled marksmen equipped for a confusing, rapidly unfolding crisis."

Many law enforcement groups have opposed Trump's suggestion to give guns to instructors. Some have also criticized the president himself for saying he would have personally rushed into the school, armed or not, after a sheriff's deputy posted in Parkland waited outside when the shooter opened fire on students and staff.

The Portland union president says arming teachers would do little but cause chaos and confusion.

"In an active shooter incident, having teachers running around a school with guns while law enforcement enters the building could make it difficult for us to differentiate between the good guys and the bad guys. It would increase the risk of innocent people—children, other teachers, and police officers—being injured or killed," Turner said.

The PPA also urged lawmakers to pass laws that would ban the sale of accessories that make legal guns more deadly and increase penalties for people who violate gun laws, commit mass shootings or use guns to perpetrate domestic violence.

Although the position itself is not unusual—urban police often support gun control measures—the PPA's break with Trump's political messaging highlights fissures that started to widen in conservative politics in the days following the most recent mass shooting.

Trump himself shocked lawmakers Wednesday when he urged Congress to bring back legislation that has long been opposed by the National Rifle Association and most Republicans.