“Impeachmint” (also “impeach-mint” or “impeach mint”) is a political flavor pun on the word “impeachment.” The term was popularized by at least 1973, with U.S. President Richard Nixon‘s possible impeachment. (He resigned on August 9. 1974.)
 
“ImPeachMint” was reportedly offered by a San Francisco ice cream parlor in January 1973. “President Impeach-mint” gum was cited in September 1973. An “Impeachment Cocktail” recipe was cited in print in October 1973. “Impeachmints” breath mints were trademarked in 1998, after the Lewinsky scandal and subsequent impeachment proceedings of President Bill Clinton.
   
 
26 January 1973, Corona-Norco Independent (Corona, CA),  “Odds and Sods” from the staff, pg. 3, col. 1:
Here’s word from Herb Caen about a San Francisco ice cream parlor that’s following up its Inaugural Week special with a new flavor called ImPeachMint.
 
OCLC WorldCat record
Double Your Pleasure, Double Your Fun…
Author: Osrin, Ray
Publisher: Plain Dealer (firm) 1973-09-28
Edition/Format: Computer file
Summary: Editorial cartoon by Ray Osrin of two female donkeys with “Dems” on their sweaters. In a spoof of the Doublemint twins, they are each carrying a large stick of gum with a label “President Impeach-mint.” The caption is “Double your pleasure, double your fun.” The cartoon is signed and dated in the lower right corner “Osrin 1973 The Plain Dealer 9/28.”
11.50” X 17.25”
 
25 October 1973, The Post-Crescent (Appleton, WI), pg. A-2, col. 1 ad:
Impeachmint Cocktail
INVENTED BY THE PRESIDENT & VICE PRESIDENT
OF CHOICE—Please don’t add water.
2 oz. Peach Brandy—I oz. Peppermint
Schnapps On The Rocks of Course
NIX-EM-WELL-With a Twist-of Lemon
(The Choice liquor shop—ed.)
 
Google News Archive
30 April 1975, The Leader-Post (Regina, Saskatchewan), “Worth repeating” (editorial), sec. 4, pg. 53, col. 2:
One company, for instance, now offers 110 different flavors—a commercial absurdity matched only by some of the names: Caramel knowledge, impeach-mint, statutory grape, to name a few.
 
Google Books
August 1986, The Rotarian, pg. 16, col. 1:
Flavors have kept pace with current events — “Lunar Cheesecake,” “Moon Shot,” “Impeach Mint” — and fads — “Beatle Nut,” “Mini’Mint,” and “Expresso.”
     
Google Books
James Beard’s Simple Foods
By James Beard and Hal Kendig
New York, NY: Macmillan Pub. Co.; Toronto: Maxwell Macmillan Canada; New York, NY : Maxwell Macmillan International
1993
Pg. 126:
Ice cream may be American by adoption, but we have done more to glorify and perfect it, and we’ve certainly come up with more weird and wonderful flavors and names for it, like Rocky Road, Impeach Mint, and Here Come Da Fudge, than any country in the world.
 
Google Books
Heroes, Honchos, & Humdingers:
A Newspaper Columnist Looks Back 30 Years
By Toby McDaniel
Springfield, IL: The State Journal-Register
1999
Pg. 427:
Nominations for flavors-of-the-month at Washington, D.C. ice cream parlors: Monica Mocha. Impeach-mint. White Water Chocolate. Oval Office Orange Pineapple. Paula’s Pistachio. Hillary Rodham Raspberry. Bubba Banana Brickie.
 
17 February 1999, Northwest Florida Daily News (Fort Walton Beach, FL), “Remembering the legendary Shingle War” by Del Stone Jr., pg. B1, col. 1:
Top six names for Ben & Jerry’s new presidential ice cream:
1. Impeach-Mint
2. Candy Pants
3. Chilly Hillbilly Vanilly
4. Subpoena Colada
5. Peppermint Fattie
6. Draft-Dodging Pot-Smoking Intern-Nailing Raspberry
 
Google Books
Strange Bedfellows:
How Late-Night Comedy Turns Democracy into a Joke
By Russell Peterson
New Brunswick, NJ: Rutgers University Press
2008
Pg. 35:
There was even talk that an ice cream company was considering marketing a new flavor, to be called “impeach-mint.”
(Of Richard Nixon—ed.)
   
Peoria (IL) Journal-Star
Local residents gear up for inaugural celebrations
By KAREN McDONALD
Posted Jan 19, 2009 @ 09:54 PM
Last update Jan 20, 2009 @ 01:15 AM
(...)
Peoria’s Spotted Cow Ice Cream parlor is serving up scoops of “presidential ice cream” and a couple of other political-themed flavors. 
(...)
Abdnour said he hopes to unveil “Impeach-mint” as a play off the impeachment trial of Gov. Rod Blagojevich.
   
Google Books
The Genius of Impeachment:
The Founders’ Cure for Royalism
By John Nichols
New York, NY: New Press
2011
Pg. ?
Impeachment had entered into the popular culture (in the 1970s—ed.), earning mention everywhere from Annie Hall to Garry Trudeau’s Doonesbury cartoons and the cover of Mad magazine to comedy bits that joked about the introduction of a new ice cream flavor: “Impeach-mint.”
 
Mad magazine
Ben & Jerry’s New Barack Obama-Themed Flavor
Tue, 05/14/2013 - 1:30pm
Author: The Editors
MOUTH WATERING-GATE DEPT.
A BEN & JERRY’S FLAVOR WE’LL SOON BE SEEING
BARACK OBAMA’S
Impeach-
Mint
Peach & Mint Ice Cream with Three Scandalous, Hard-to-Swallow Flavors Sure to Leave a Bad Taste in Your Mouth
   
(Trademark)
Word Mark IMPEACHMINTS
Goods and Services (ABANDONED) IC 030. US 046. G & S: BREATH MINTS
Mark Drawing Code (1) TYPED DRAWING
Serial Number 75564476
Filing Date October 5, 1998
Current Basis 1B
Original Filing Basis 1B
Owner (APPLICANT) Mark Chappell John Ludka, Mark Chappell PARTNERSHIP 3249 Petaluma Avenue Long Beach CALIFORNIA 90808
Attorney of Record Russell C. Pangborn
Type of Mark TRADEMARK
Register PRINCIPAL
Live/Dead Indicator DEAD
Abandonment Date August 10, 1999
 
(Trademark)
Word Mark IMPEACHMINTS
Goods and Services IC 030. US 046. G & S: Candy mints. FIRST USE: 20050101. FIRST USE IN COMMERCE: 20050411
Standard Characters Claimed
Mark Drawing Code (4) STANDARD CHARACTER MARK
Serial Number 78702297
Filing Date August 29, 2005
Current Basis 1A
Original Filing Basis 1A
Published for Opposition August 8, 2006
Registration Number 3162142
Registration Date October 24, 2006
Owner (REGISTRANT) Unemployed Philosophers Guild CORPORATION NEW YORK 105 Atlantic Ave. Brooklyn NEW YORK 11201
Type of Mark TRADEMARK
Register PRINCIPAL
Affidavit Text SECT 15. SECT 8 (6-YR).
Live/Dead Indicator LIVE