The popular “lightbulb joke” doesn’t have one standard version that involves politicians. “How many politicians does it take to change a light bulb?” was cited as a headline in December 1979, but there wasn’t a punchline.
 
A somewhat frequent version was cited in 1996:
 
Q: How many politicians does it take to change a light bulb?
A: Two; one to change it and one to change it back again.
 
“How many politicians does it take to screw in a light bulb? Not sure, first they have to figure out which way to spin it” is a popular version.
     
   
Wikipedia: Lightbulb joke
A lightbulb joke is a joke that asks how many people of a certain group are needed to change, replace, or screw in a light bulb. Generally, the punch line answer highlights a stereotype of the target group. There are numerous versions of the lightbulb joke satirizing a wide range of cultures, beliefs and occupations.
 
Early versions of the joke, popular in the late 1960s and the 1970s, were used to insult the intelligence of Poles (“Polish jokes”).
   
1 December 1979, Boston (MA) Herald American, pg. E9, col. 1: 
How many politicians does it take to change a light bulb?
Russell Baker
 
Google Books
he C³ Experience:
Counseling, Computers, and Creative Change
By Garry Richard Walz and Jeanne Bleuer
Ann Arbor, MI: Eric Counseling and Personnel Services Clearinghouse
1984
Pg. 61:
How many politicians does it take to change a light bulb? (Just one—but he also needs a crowd to tell him whether to turn it to the right or to the left.)
 
7 April 1984, Gettysburg (PA) Times, “Golf balls, tin cans, monkeys” by Geoffrey W. Taylor, pg. 4, col. 1:
How many politicians does it take to change a light bulb
25. One to hold the bulb and 24 to turn the ladder.
 
4 September 1989, St. Petersburg (FL) Times, “Characters bring Citrus nights to life” by Jan Glidewell, pg. 6:
Then Little Rebel told me her joke of the month:
 
“How many politicians does it take to screw in a light bulb?”
 
The answer is “two.”
 
“It takes one to assure everybody that the situation is absolutely and completely under control,” she said, beginning to chuckle, “and one to screw the light bulb in to the water faucet.”
 
10 May 1990, Syracuse (NY) Herald-Journal, “Didja hear the one?” by Doug Robarchek, HJ sec., pg. 15, col. 1:
DIM BULBS
Q. How many politicians does it take to change a light bulb?
A. Twelve. One to promise a “brighter point of light”; a task force of 10 to travel to Indonesia to examine lightbulb changing techniques, and one to explain why government can now only afford a 40-watt bulb.
 
23 January 1991, The Stonewall Argus/Teulon Times (Stonewall, Manitoba), “Need a light bulb changed?” by Pastor Henry A. Ozirney, pg. 25, col. 2:
“How many politicians does it take to change a lightbulb?” “Only one—it only takes one politician to screw anything else up.”
 
Google Groups: rec.humor
Light Bulbs
Barny Shergold
7/18/94
(...)
6. How many politicians does it take to change a light-bulb?
Four, one to change it and the other three to deny it.
 
OCLC WorldCat record
How many politicians does it take to ...?
Author: Wanda Jo Peltier
Publisher: [Place of publication not identified] : W.J. Peltier, ©1996.
Edition/Format:   Print book : English
Subjects
Oklahoma—Politics and government.
 
13 May 1996, Atlanta (GA) Journal-Constitution, “For healthy outlook, treat yourself to funny sites” by Amanda Husted, pg. C8:
Light Bulb Jokes, which will turn on your sense of humor. Sample: “How many politicians does it take to change a light bulb? Two; one to change it and one to change it back again.”
 
Google News Archive
7 November 1999, The Free Lance-Star (Fredericksburg, VA), “Letters to the Editor, pg. E2, col. 2:
How many politicians does it take to change a light bulb? The correct answer is one. He (or she) stands on a chair holding the bulb, while his handlers, political action committees and soft money supporters turn the chair around and around.
(...)
Larry D. Greene
Monross
 
Google Books
Man Walks into a Bar:
Over 6,000 of the Most Hilarious Jokes, Funniest Gut-Busting One-Liners
By Stephen Arnott, Mike Haskins
Berkeley, CA: Ulysses Press
2007
Pg. 256:
How many politicians does it take to change a light bulb?
It depends on how many it took under the previous government.
 
Google Books
The Big Ass Book of Jokes
By Rudy A. Swale
Berkeley, CA: Ulysses Press
2009
Pg. 330:
How many politicians does it take to change a light bulb?
Two. One to change it and one to change it back again.
 
Google Books
The Mammoth Book of Really Silly Jokes
By Geoff Tibballs
London: Constable & Robinson Ltd
2011
Pg. 273:
How many politicians does it take to change a light bulb?
Four. One to change it and the other three to deny it.
 
Google Books
Doug Kass on the Market:
A Life on TheStreet
By Douglas A. Kass
Hoboken, NJ: John Wiley & Sons, Inc.
2014
Pg. 493:
Question: How many politicians does it take to screw up our economy?
Answer: 537 (436 members of the House, 100 members of the Senate and one president)
 
Google Books
The Best Joke Book (Period):
Hundreds of the Funniest, Silliest, Most Ridiculous Jokes Ever
By William Donohue
Avon, MA: Adams Media
2014
Pg. 104:
How many politicians does it take to screw in a light bulb?
One, but boy does it get screwed good.