A “turd sandwich” is something unpalatable that, for some reason or other, is being served up. The term was popularized on the “Douche and Turd” episode of the television show South Park that aired on October 27, 2004; the choices in an election were between a “giant douche” and a “turd sandwich.”
 
President Barack Obama further popularized the term in March 2011 when he called his military options in Libya a “turd sandwich.”
 
The term “shit sandwich” has been cited in print since at least the 1960s. The similar term of “crap sandwich” became widely used in 2008, when Congressman John Boehner (R-OH) called the proposed $700 billion financial rescue bill by that sandwich name.  “Satan sandwich”—a euphemism for the terms above—was used by Congressman Emanuel Cleaver (D-MO) to describe a 2011 budget deal that he didn’t like.
 
       
Wikipedia: Douche and Turd
“Douche and Turd” is episode 119 of South Park. It was originally broadcast on October 27, 2004, just before the 2004 presidential election.
 
Plot
During a pep rally at the South Park Elementary School, a group of local PETA eco-terrorists protests the use of a cow as a mascot (for “the 47th time”). The school agrees to pick a new mascot, and the students are told to vote for said new mascot. Embarrassed by the bland choices, the kids decide to fill in a joke candidate but disagree as to whether it should be a “giant douche” or a “turd sandwich.” Kyle rallies his friends to fill in the giant douche, and Cartman gathers support for the turd sandwich.
 
Urban Dictionary
turd sandwich
1. a presidential candidate whom campaigns against a giant douche. introduced by the creators of south park. 2. two pieces of bread with a juicy turd in the middle (a nutella sandwich?)
1. sometimes, its always the choice between a giant douche and a turd sandwich. 2. after the hot blumpkin, the couple both enjoyed a nice hot turd sandwich
by KDIZZO Mar 24, 2005
     
Google Books
Crawdaddy
Issues 13-20
1968
Pg. ?: 
...and as detestable as a turd sandwich.
 
Google Books
Orion Arm
By Julian May
New York, NY: Ballantine Pub. Group
1999
Pg. ?:
“Stick your head up your ass,” Simon told his oldest son, “and eat a turd sandwich.”
   
Google Books
Running Loose
By Chris Crutcher
New York, NY: HarperTempest
2003
Pg. 10:
Dakota says if we always judged things by how they ended up, life would more than likely seem like one turd sandwich after another, given the way things have a tendency to end up.
       
The Blaze
Did Obama Call the Libyan Situation a ‘Turd Sandwich?’ (NBC Anchor Says ‘Yes’)
Posted on March 30, 2011 at 10:35am by Mike Opelka
Don’t call it a Kinetic Military Action!
 
Yet another neck-snapping moment provided by one of the MSNBC anchors.
 
Savannah Guthrie was part of the ‘panel’ on Meet The Press this past Sunday and she gave us all one for the video clip file. This was all happening in advance of the President’s Monday night address to the nation.
 
“And the President is obviously not happy with his set of choices. One person told me, in a meeting he called this military action in Libya a ‘turd sandwich’ but he was quoting one of his national security aides who likes to use that term.”
 
Examiner.com
Stephen Colbert covers the ‘turd sandwich’ of an intervention in Libya (Video)
March 30th, 2011 10:43 am ET .
Ryan Witt
Political Buzz Examiner
Last night Stephen Colbert illustrated the ever-changing language to describe the war/intervention/conflict/humanitarian mission in Libya.  Many political pundits have accused the Obama administration of not having a clear message on the Libyan mission.  Colbert made fun of the dilemma for the Obama administration, and then referred to a clip of Savannah Guthrie from MSNBC who reported that the President himself called the intervention a “turd sandwich”  Colbert then introduces his own coverage of the “Turd Sandwich in Libya.”
 
OpEdNews
March 30, 2011 at 23:38:04
Our Billion Dollar Turd Sandwich
By David Swanson
So President Obama has been quoted calling his war in Libya a turd sandwich, while Juan Cole calls it philanthropy, and Ed Schultz praises it as vengeance against this month’s Adolph Hitler. The last time we bombed this particular Hitler we took out his daughter, among other people.