“Walk and chew gum at the same time” (stupid or uncoordinated)

Someone who is uncoordinated (or just stupid) might be described as a person who “can’t walk and chew gum at the same time.” The term is recorded in a Texas newspaper in 1954. President Lyndon Johnson allegedly said that then-Congressman (and later president) Gerald Ford couldn’t “fart and chew gum at the same time.” 
 
As early as the 1900s, it was observed that women talk a lot and chew gum a lot, but don’t “talk and chew gum at the same time.” Entertainer and cowboy philosopher Will Rogers was described in 1926 as “the only man in the world who can chew gum and talk sense at the same time.” It’s probable that the saying “walk and chew gum at the same time” developed from the earlier “talk and chew gum at the same time.”
 
   
The Free Dictionary
walk and chew gum (at the same time)
to be able to do more than one thing at a time
Officials say they have to plan for all kinds of possibilities, that they have to be able to walk and chew gum at the same time.
 
Google Books
The Quote Verifier:
Who said what, where, and when
By Ralph Keyes
New York, NY: St. Martin’s Press
2006
Pg. 23:
“He can’t walk and CHEW GUM at the same time.”
Pg. 24:
When Ford became president in 1974, it was widely recalled in the press that Lyndon Johnson once said Ford was so dumb he couldn’t walk and chew gum at the same time. According to Washington insiders, what the earthy LBJ really said was that Jerry Ford couldn’t “fart” and chew gum at the same time.
Verdict: Credit LBJ for the earthier version.
   
(Oxford English Dictionary)
U.S. colloq. to walk and chew gum at the same time and variants: to perform two simple tasks at the same time. Chiefly in negative contexts, implying lack of ability, competence, or wherewithal.
1956 Denton (Maryland) Record-Chron. 24 Dec. II. 2/2 He can’t walk and chew gum at the same time.
1976 SubStance 32 5 Its [sc. the law’s] authenticity..is best confirmed when the task of executing it falls on the one you would least expect (on someone born in a log cabin, for example, or on a man who can’t walk and chew gum at the same time).
1984 N.Y. Times (Nexis) 21 June A22/4 We all know those business executives who find it difficult to walk and chew gum simultaneously.
2001 New Republic 1 Oct. 23/1 Being a superpower means being able to walk and chew gum at the same time.
       
9 February 1907, Iowa City (Iowa) Daily Press, pg. 2, col. 3:
“A woman cannot talk and chew gum at the same time, anyhow,” said he.
   
27 December 1926, Los Angeles (CA) Times, pg. A2: 
MAYOR WILL ROGERS, the only man in the world who can chew gum and talk sense at the same time, was an exceedingly busy man at his mansion in Beverly Hills.
     
Newspapers.com
16 March 1954, Paris (TX) News, “Billboard” by Bill Thompson, pg. 7, col. 1:
AFTER LOOKING over his crop of Texarkana High talent for next football season, Coach Watty Myers appeared a bit disappointed. He cast some immediate reflections on their football ability. “Why they can’t walk and chew gum at the same time,” Myers groaned.
 
24 December 1956, Denton (TX) Record-Chronicle, sec. 2, pg. 2, col. 4:
A classic comment by a local basketball player referring to a teammate’s co-ordination: “He can’t walk and chew gum at the same time.”
 
29 February 1964, El Paso (TX) Herald-Post, pg. B1, col. 1:
And Bob Rule of the Houston press tells about the rookie baseball player who was so poorly coordinated that he couldn’t walk and chew gum at the same time.
   
Historical Digital Collegian Archive
13 March 1965, Daily Collegian (Penn State University), “A Lot on Sports” by John Lott:
“When 1 came up here, t couldn’t walk and chew gum at the same time.”
 
29 August 1965, Los Angeles (CA) Times, Calendar section, pg. B3:
He’d never danced before, and likes now to recall his high school coach s comment: “Boone is so uncoordinated he can t chew gum and walk at the same time.”
   
15 April 1966, Amarillo (TX) Globe-Times, ‘Turnstile” by Thomas Thompson, pg. 2, col. 1:
He had a problem of coordination—like walking and chewing gum at the same time.
 
Google News Archive
24 January 1967, Eugene (OR) Register-Guard, “Kramer Says: ‘I’m Happy to be Just Anywhere,’” pg. 3B, col. 5:
“I’ll tell you, I was 17 before I could walk and chew gum at the same.”
(Green Bay Packer offensive guard Jerry Kramer—ed.)
   
Google Books
21 March 1968, Jet, pg. 30:
“And I mailed it to my football coach who once said I couldn’t chew gum and walk at the same time.”
(Bill Cosby—ed.)
     
Newspapers.com 
21 October 1973, Lowell (MA) Sunday Sun, “Ford no Einstein but strong voice in Congress,” pg. E4, col. 1:
WASHINGTON—It is, of course, grossly slanderous to suggest, as Lyndon Johnson once did, that Vice President-designate Gerald R. Ford is so dumb he “can’t chew gum and walk at the same time.”
 
Google Books
A Ford, Not a Lincoln
By Richard Reeves
New York, NY: Harcourt Brace Jovanovich
1975
Pg. 25:
What Johnson actually said was, “Jerry Ford is so dumb he can’t fart and chew gum at the same time.”