With the rising threat of armed criminals invading schools, several Americans are questioning whether a prohibition of the 2nd amendment or other means of gun control are needed. However, there is a much simpler solution which eliminates the need for gun control and effectively stops criminals dead in their tracks. This is putting a fire extinguisher in every US classroom.
Fire extinguishers, surprisingly, are very good at making people pass out forcibly from a distance. This is because it forces CO2 into a person's lungs, which gives an effect similar to holding your breath.
It also disarms criminals, making them unable to fire a weapon. After the gunman passes out, teachers can call 911 to arrest him/her.
This would only cost around $200 million, less than our Iraq war budget.