The United States of America has sometimes been dubbed the “United States of Amnesia.” These critics charge that Americans often forget things—usually the bad things, like slavery. “United States of Amnesia” has been cited in print since at least 1939, when American journalist Christopher Morley (1890-1957) wrote:
 
“Incessant publicity has turned us into a United States of Amnesia; and if you remember nothing of what has happened in the past you’re unlikely to foresee much of what will happen in the future.”
 
American writer Gore Vidal (1925-2012) used the term since at least 1988, and a documentary film about his life was titled Gore Vidal: The United States of Amnesia (2013).
 
[This entry was prepared with research assistance from the Quote Investigator.]
 
   
Wikipedia: Gore Vidal
Gore Vidal (/ˌɡɔr vɨˈdɑːl/; b. Eugene Louis Vidal; 3 October 1925–31 July 2012) was an American writer (of novels, essays, screenplays, and stage plays) and a public intellectual known for his patrician manner, epigrammatic wit, and polished style of writing. As Eugene Louis Vidal, he was born to a political family; his maternal grandfather, Thomas Pryor Gore, served as United States senator from Oklahoma (1907–21 and 1931–37). As Gore Vidal, he was a Democratic Party politician who twice sought elected office; first to the United States House of Representatives (New York State, 1960), then to the U.S. Senate (California, 1982).
 
Wikipedia: Gore Vidal: The United States of Amnesia
Gore Vidal: The United States of Amnesia is a 2013 documentary film about the life and career of author Gore Vidal. It premiered at Tribeca Film Festival in 2013.
 
UNZ.org
4 March 1939,

, “Mind Rain Precautions (Or, Advice to the Truthlorn)” by Christopher Morley, pg. 12:
This overvitalized Publicity is an onslaught on one of the most precious human faculties, memory. If you stun people’s memories you can do anything with them. The daily jolt becomes necessary because the previous one is already forgotten. (Pg. 14—ed.) Incessant publicity has turned us into a United States of Amnesia; and if you remember nothing of what has happened in the past you’re unlikely to foresee much of what will happen in the future.
     
5 March 1948, The Morning Herald (Hagerstown, MD), “The Once Over” by H. I. Phillips, pg. 16, col. 6:
You are interpreting the initials U. S. A. as meaning United States of Amnesia. You are singing it “My Country, ‘Tis of Thee, Sleeping Land” of Stupidity.”
 
OCLC WorldCat record
Old Rottenhat
Author: Robert Wyatt
Publisher: New York : Thirsty Ear Recording, Inc., p©1986, 1998.
Edition/Format:   Music CD : CD audio : English
Event notes: Recorded, 1984, West Studios, Acton, by John McGowan ; 1985, Acre Lane Studios, Brixton by Bill Gilonis.
Description: 1 sound disc : digital ; 4 3/4 in.
Details: Compact disc.
Contents:
Alliance—
The united states of amnesia—
 
Google News Archive
19 October 1986, Milwaukee (WI) Journal, “Listen up!,” pg. 9E, cols. 3-4:
Robert Wyatt—“Old Rottenhat”—Grammavision
(...)
But on “The United States of Amnesia,” portraying America’s eerie ability to always believe the best of itself, Wyatt hits us where we live.—DAVE LUHRSSEN
 
25 March 1988, Washington (DC) Times, “Vidal on ‘U.S. of Amnesia’” by Ann Geracimos, pg. E9, col. 2:
Gore Vidal’s “stump speech,” which he delivered twice in four days here with only slight variations, concerns U.S. decadence and decline. “You can’t say things too often in the United States of Amnesia,” he notes.
 
Google Books
Past Imperfect:
History According to the Movies
Edited by Mark C. Carnes
New York, NY: Holt
1996
Pg. 9:
And television’s continuous old movies function as night school, a great repository of historical consciousness in these United States of Amnesia. For many, Hollywood History is the only history.
     
Google Books
Black Mutiny:
The Revolt on the Schooner Amistad
By William A. Owens
Baltimore, MD: Black Classic Press
1997
Pg. I:
It is not overstating the case to suggest that, when it comes to race, we are living in the United States of Amnesia. America cannot solve its race problem because it cannot afford to remember what it has been through, or more accurately, what it has made its Black citizens endure: the horrible cowardly, vicious legacy of racial domination stoked by religious belief and judicial mandate.
 
Google Books
Perpetual War for Perpetual Peace:
How We Got to Be So Hated, Causes of Conflict in the Last Empire
By Gore Vidal
New York, NY: Thunder’s Mouth Press/Nation Books
2002
Pg. IX:
In the last six years, two dates are apt to be remembered for longer than usual in the United States of Amnesia: April 19, 1995, when a much-decorated infantry soldier called Timothy McVeigh blew up a federal building in Oklahoma City, killing 168 innocent men, women, and children.