Politics and religion.

[Grace]

I remember President Kennedy being killed in public by a nut with a rifle.
There seems to be no way to limit the sale of guns to stable people.

I just finished a book about the Secret Service. Back in 1963 Kennedy was warned, repeatedly, not to go to Dallas. By Senator Fulbright, by Adlai Stevenson, and others. Back then only 2 Secret Service agents had gone to Dallas to check things out. Not one building on the route was checked. These days, whenever there is a motorcade, buildings along the route are checked. Empty offices are sealed shut. Presidential cars are bullet proof.

Today, Oswald would not have been able to reach that window. Kennedy would not have been in an open car.