“Do you solemnly swear or affirm that you will tell the truth, the whole truth, and nothing but the truth, so help you god?” is a sworn oath. Politicians are often said to have a problem telling the truth, leading to the joke:
 
Q. What do you get when you ask a politician to tell “the truth, the whole truth, and nothing but the truth”?
A. Three different answers.
 
The joke has been cited in print since at least October 2007. In early 2008, “Clinton” (Hillary Clinton was then running for president) replaced “politician.”
 
   
Wikipedia: Sworn testimony
United States
Oath:
Do you solemnly swear or affirm that you will tell the truth, the whole truth, and nothing but the truth, so help you god?
Note: In some cases “so help you god” may be replaced with “under pains and penalties of perjury”.
     
International Military Forums
Team Infidel
October 22nd, 2007
Q. What do you get when you ask a politician to tell “the truth, the whole truth, and nothing but the truth”?
A. Three different answers.
     
Grasscity.com Forums
Blunt_Babe
10-23-2007, 02:41 AM
Cus it’s always fun to pick on Politicains
Q. What do you get when you ask a politician to tell “the truth, the whole truth, and nothing but the truth”?
A. Three different answers.
 
International Jokes
Sunday, 24 February 2008
Clinton Jokes
(...)
What do you get when you ask Clinton to tell “the truth, the whole truth, and nothing but the truth”?
Three different answers.
     
Sabong Cockfighting and Gamefowl Posting Pit
WiNgEd CrEaToR
February 27th, 2008, 07:44 AM
Originally Posted by stupid_crook
JOKE OF THE DAY
Q. What do you get when you ask a politician to tell “the truth, the whole truth, and nothing but the truth”?
A. Three different answers.
 
Google Books
Giggles, Gags, and Quips
By Thomas F. Shubnell
Self-published by Thomas F. Shubnell
2008
Pg. 189:
What do you get when you ask Clinton to tell, “the truth, the whole truth, and nothing but the truth”? Three different answers.
 
Annuity Think Tank
Gridlock for Gals at year end under Split Congress?
22 October 2012
The Debates have once again proved that what you get when you ask a politician to tell the truth, the whole truth and nothing but the truth that you will get three different answers so it is not surprising that boomer women really do fear their financial future more than Mitt Romney.