“Misery acquaints a man with strange bedfellows,” wrote William Shakespeare in his play, The Tempest (1611). “Politics makes strange bedfellows” (or, “Politics make strange bedfellows”) appeared in print by the early 1800s and came into frequent use by the 1830s.
   
“If politics makes strange bedfellows, it is due to their fondness for the same bunk” (a play on the word “bunk,” meaning both “bunk-bed” and “bunkum,” or “nonsense”) is a humorous variation that first appeared in the 1920s.
 
“Politics doesn’t make strange bedfellows—marriage does” is a modern take on the old saying.
 
 
The Free Dictionary
Politics makes strange bedfellows.
Prov. People who would normally dislike and avoid one another will work together if they think it is politically useful to do so. Jill: I never would have thought that genteel, aristocratic candidate would pick such a rabble-rousing, rough-mannered running mate. Jane: Politics makes strange bedfellows.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002
 
Google Books
The Quote Verifier:
Who said what, where, and when
By Ralph Keyes
New York, NY: St. Martin’s Press
2006
Pg. 170:
“POLITICS makes strange bedfellows.” In The Baviad and Maeviad (1797), English editor-author William Gifford wrote, “I can only say that politics, like misery, ‘bring a man acquainted with strange bedfellows.’” ‘Verily,” agreed an American press commentator thirty-five years later, “politics do (pg. 171—ed.) make strange bedfellows.” Seven years after that, in 1839, onetime New York mayor Philip Hone wrote in his diary that “party politics, like poverty, ‘bring men acquainted with strange bedfellows.’” In 1851, a Wisconsin political analyst compressed this thought into “Politics makes strange bedfellows.” The root of that saying can, of course, be found in The Tempest (1611), where Shakespeare wrote that “misery acquaints a man with strange bedfellows.”
(...)
Verdict: A modular saying built on Shakespeare’s foundation.
   
Google Books
The Baviad, and Maeviad
9th Edition
By William Gifford
London: Printed for Becket and Porter
1811
Pg. 108:
If that respectable name was not abused on the occasion, I can only say that politics, like misery, “bring a man acquainted with ‘strange bedfellows!’”
   
1 December 1818, The British Critic, “Brown’s Memoirs of Howard, the Philanthropist,” pg. 583: 
But literature, like politics and poverty, “brings a man acquainted with strange bed-fellows.”
 
21 June 1829, The Age (London), pg. 197, col. 3:
The wonder is, how his Grace should have ever countenanced Lord Anglesea or Sir George Murray; but politics, like poverty, gives us “strange bed-fellows.”
 
23 September 1832, The Age (London), pg. 308, col. 2:
We little expected to live unto a day when we should back Greek JOE—but politics, like poverty, acquaint us with strange bedfellows, and exhibit unlooked-for combinations.
 
16 October 1832, Richmond (VA) Enquirer, pg. 2:
Mr. King will not thank us for putting him in company with Col. Webb—but politics, like “adversity, makes us acquainted with strange bed-fellows.”
 
21 May 1834, Jamestown (NY) Journal, pg. 2:
We are also receiving the “New York Times,” successor to the late

, and conducted by Messrs. Holland, Sanford and Bedient, gentlemen of too much talents and character to be associated with Crosswell and Blair. But “politics make strange bed-fellows.”
 
14 October 1834, Gloucester (MA) Democrat, pg. 2:
“Politics and Poverty make us acquainted with strange bed fellows.”
 
Google Books
August 1927, Tax Facts, pg. 63, col. 2:
“If politics makes strange bedfellows it is due to their fondness for the same bunk.”— Florence (Ala.) Herald.
 
7 September 1927, Port Arthur (TX) News, pg. 4, col. 7:
They say politics makes strange bedfellows. Possibly it is because of their fondness for the same bunk.—The Humboldt Times. (Eureka, Calif.)