“A nation/society of sheep will beget a government of wolves” is often credited to American broadcast journalist Edward R. Murrow (1909-1965). The saying means that the electorate cannot be “sheep” or they will be taken over by “wolves” (such as a totalitarian dictatorship).
   
“A society of sheep must in time beget a government of wolves” has been credited to French philosopher Bertrand de Jouvenel (1903-1987) since at least 1949. It is probable that de Jouvenel originated the saying.
 
“A nation of sheep” was popularized from the title of a 1961 book about United States foreign policy by William Lederer (1912-2009). “Nation of sheep, ruled by wolves, owned by pigs” is an expanded saying.
 
   
Wikipedia: Bertrand de Jouvenel
Bertrand de Jouvenel des Ursins, usually known only as Bertrand de Jouvenel  October 1903 – 1 March 1987) was a French philosopher, political economist, and futurist.
     
Wikiquote: Wolves
Unsourced
A society of sheep must in time beget a government of wolves.
Bertrand de Jouvenal
 
Wikiquote: Government
Unsourced
A nation of sheep will beget a government of wolves.
Edward Murrow
   
3 July 1943, Burlington (NC) Daily Times-News, “To Thomas Jefferson: A Tribute,” pg. 4, col. 2:
ON TYRANNICAL GOVERNMENT
We affirm, in the face of unparalleled examples, our agreement with your abhorrence of government by tyranny: “To have an idea of the curse of existence under (governments of force), they must be seen. It is a government of wolves over sheep.”—Letter to James Madison, 1787.
     
Google Books
The Reader’s Digest
v. 54 - 1949
Pg. 7:
Bertrand de Jouvenel: A society of sheep must in time beget a government of wolves.
 
Newspapers.com
8 May 1949, The Palm Beach Post-Times (West Palm Beach, FL), “Misery Loves Company” (editorial), pg. 4, col. 1:
A great writer once said, “a society of sheep is certain to build a government of wolves.”
 
Newspapers.com
19 May 1949, Windsor (ON) Daily Star, “Letter Box,” pg. 19, col. 4:
In closing I would like to recall a well-known quotation which can bear repetition at this time, and any time:
 
“A society of sheep begets a government of wolves.”
S. LORE.
Windsor.
 
Newspapers.com
27 May 1949, The News-Herald (Franklin and Oil City, PA), “Working for a Better World” by Senator Edward Martin, pg. 4, col. 1:
The French writer, Bertrand de Jouvenel, was so correct when he said:
 
“A society of Sheep must in time beget a government of Wolves.”
 
Newspapers.com
13 June 1950, The News-Herald (Franklin and Oil City, PA), pg. 1, right masthead:
Evening Thought
A society of sheep must in time beget a government of wolves.
—Bertrand de Jouvenel.
   
14 June 1950, New Orleans (LA) Times-Picayune, “‘Longism’ Scored in Lafargue Talk” by George Jackson, pg. 7, col. 1:
Lafargue admitted that Huey Long gave the state “many improvements.” But he added that “we are still paying the cost on public debt and high taxes.”
“Government of Wolves”
“His political philosophy left a society of sheep and a government of wolves,” Lafargue said.
       
Google Books
Shirtsleeve Economics;
A commonsense survey
By William A Paton
New York, NY: Appleton-Century-Crofts
1952
Pg. 263:
The need for eternal vigilance on the part of the citizenry to keep government within bounds is implied in Bertrand de Jouvenel’s famous remark: “A society of sheep must in time beget a government of wolves.”
 
Google Books
Second encyclopedia of stories, quotations, and anecdotes
Edited by Jacob Morton Braude
Englewood Cliffs, NJ: Prentice-Hall
1957
Pg. 150:
A society of sheep must in time beget a government of wolves. — BERTRAND DE JOUVENEL
 
20 March 1958, Richardson (TX) Echo, pg. 7, col. 6:
A society of sheep must, in time, beget a government of wolves.—Bertrand DeJouvenel.
 
23 February 1977, Trenton (NJ) Evening Times, pg. A11, col. 2:
“A society of sheep must in time beget a government of wolves.”
—Bertrand de Jouvenal.
   
Google Books
The Ramblings Of A Realist
By Charlie Walker
Biggleswade, Beds: Watkiss Studios Ltd.
2000
Pg. 24:
A society of sheep must in time beget a government of wolves and it is useless for the sheep to pass resolutions in favour of vegetarianism whilst the wolf remains of a different opinion.
Dean William. R Inge.