When the U.S. was first founded, every male the age of 13 was required to maintain and be competent with firearms. Such persons were required to carry out both military and constabulary duties when their local community required it. Persons unable or unwilling to carry out such duties were required to pay a fee and those funds were used to pay for munitions and training for those who were willing to fight.
The problem we have in society is everyone is obsessed with living forever and are scared into paralysis of anything deemed "dangerous". The common U.S. mindset is "I pay taxes so I don't have to serve" also known as the "not my job" mentality.
I am all for citizens in the U.S. receiving basic firearms safety training in public school as a requirement. Every able bodied adult in the U.S. should have to volunteer a minimum of 16 hours a month to their local police department and receive adequate training to carry out their volunteer duties. That would include firearms training for their issued duty weapon.
Anyone who is a conscientious objector would be allowed to opt out by volunteering with their local fire department or pay more in taxes to support their local police agencies.