There has probably never been a civil and polite political campaign in America and I doubt that there ever will be. It just is not the American way.
Beginning with the campaigns of Thomas Jefferson there has always been name calling and character assassination in every presidential election.
John F. Kennedy, in his book, Profiles in Courage, traced this characteristic of political campaigns.
I recall that he quoted the great Texas hero, Sam Houston, as saying of his political opponent that “he has all the characteristics of a dog except loyalty!”
You can’t get more personal than that.