Editor’s note: This is the 51st in a series of essays on the history and meaning of the American political tradition.
In 1893, in commemoration of the 400th anniversary of Columbus’ discovery of America, the city of Chicago hosted a World’s Fair, appropriately named “The Columbian Exposition.” It was a celebration of the world’s achievements in science and industry, architecture, literature and the fine arts, and of the progress of American civilization. 
Among the events marking the opening of the fair were academic lectures, among them a scholarly paper read by a young historian from Wisconsin, Frederick Jackson Turner (1861–1932), titled “The Significance of the Frontier in American History.” The title summarized his thesis, which has since become known among historians as “the frontier thesis.” Turner began by observing that geographically, there was no longer any physical frontier, which is to say, a boundary beyond which there was land free for the taking. Nevertheless, he asserted that the frontier was alive and well, for the very idea of it had taken root in the mind of the nation and become determinative of American national identity. What memory is to personal identity, history is to a nation. The popular history of the frontier had become the ruling narrative of the nation, for good or for ill, the ruling symbol of American purpose and values, and the hallmark of the American character. 
Turner’s paper became a defining moment in American historiography. Even now, after much critical discussion, it is well worth pondering.
Turner conceived of the American frontier not as a settled boundary but as a moving line, which, from the founding of the nation until the close of the nineteenth century, headed west. The first frontier was the Atlantic coast, then the Alleghenies, next, the Mississippi River, thence it made its way across the Great Plains, to the Rockies, passed through the Great Basin and reached its limit at the shores of the Pacific. Reading Turner is a good primer in geography.
But to be the source of all that he claimed for it, Turner imagined the frontier to be something more than a geographical line. He imagined it as the symbol of a form of life, whose vitality flowed from the promise of free land beyond the frontier, which continued to move west — imagine wagon trains moving across the prairie, or the railroad. And even after the frontier had reached its limit and became a fixed boundary, Turner supposed that it continued to shape the American character, for good or for ill.
What gave shape to this form of life were the circumstances of its beginning. Every westward movement involved a departure from civilization and a return to primitive conditions; the pioneer exchanged his European dress for the hunting shirt and moccasin; he travelled in a birch bark canoe; he lived in a log cabin and planted Indian corn. There was a recurring need to reinvent civilization, which may not have always involved reinventing the wheel, but surely refashioning it and refitting it, transforming it into an instrument of power. 
Yet this recurrent return to primitive conditions left a residue of harshness or coarseness in the moral and political character of America that remains today. It is evident in the extremes of populism of the left and right. 
Hence the proviso, for good or ill, is a necessary refrain. “So long as free land exists,” economic opportunity exists for those willing to seize it, and with it comes political power, and from this a form of democratic polity that borders on populism. Which led Turner to issue this warning: “The democracy born of free land, strong in selfishness and individualism, intolerant of administrative experience and education, and pressing individual liberty beyond its proper boundary, has its dangers as well as its benefits.” He worried that Individualism in America had encouraged a corrosive suspicion and hostility toward government, raised private right above civic responsibility, encouraged demagoguery, elevated the spoils system over the rule of law, and other political wrongs. 
The poet Carl Sandburg captured the ambivalence of the culture of the frontier in his poem “Chicago”:
“Hog Butcher for the World,
   Tool Maker, Stacker of Wheat,
   Player with Railroads and the Nation’s Freight Handler;
   Stormy, husky, brawling,
   City of the Big Shoulders:
 
They tell me you are wicked and I believe them, for I have seen your painted women under the gas lamps luring the farm boys.
And they tell me you are crooked and I answer: Yes, it is true I have seen the gunman kill and go free to kill again.
And they tell me you are brutal and my reply is: On the faces of women and children I have seen the marks of wanton hunger.
And having answered so I turn once more to those who sneer at this my city, and I give them back the sneer and say to them:
Come and show me another city with lifted head singing so proud to be alive and coarse and strong and cunning.
Flinging magnetic curses amid the toil of piling job on job, here is a tall bold slugger set vivid against the little soft cities;
Fierce as a dog with tongue lapping for action, cunning as a savage pitted against the wilderness.”
 
Turner’s warning and Sandburg’s brash celebration of Chicago could have been written yesterday. “The more things change, the more they remain the same.”
Finally, the history of the moving frontier is one of conquest and of violence, for the land beyond the frontier was never free for the taking. Among the sources I have used in preparing this essay is a trilogy by the historian Richard Slotkin that narrates the history of the Frontier from the seventeenth through the twentieth centuries; the titles almost tell it all: “Regeneration through Violence,” “The Fatal Environment,” “Gunfighter Nation.” Slotkin’s long and detailed, yet very readable volumes, offer proof of Turner’s thesis. He shows the presence of the frontier myth in our national culture from James Fenimore Cooper’s “Leatherstocking” tales through accounts of Custer’s last stand, and on into the 20th century. 
Postscript: Turner’s original paper, along with others on the same theme, are in a volume titled “The Frontier in American History.” It is available in paperback. Visit your local bookshop — online if you have to.