But if Bloomberg is looking to escape anything about his the way his critics paint him – the cloistered Northeasterner of a certain age—it might not have done him much good. While "chopped liver" has gone mainstream and stuck around, "(chopped) chicken liver" puts him in an older, more Northeastern group.

The expression owes its roots to the cuisine brought over by Eastern European Jewish immigrants like Bloomberg’s own ancestors. The pâté-style chopped liver served as a side dish on Jewish tables (known as gehakte leber in Yiddish) has traditionally been made from the livers of calves or, yes, chickens. According to word sleuth Barry Popik, chopped liver became a popular dish among Jewish New Yorkers by around 1910, and a few decades later, “chopped liver” and its variants began entering the lexicon via playful turns of phrase. Complaints about being treated as nothing more than “chopped liver” spread especially among the entertainment industry, which brought so much Yiddish-inflected humor to the masses.

The earliest known example in print, as Kara Kovalchik reported on Mental Floss, appears in a 1949 semi-autobiographical novel by the comedian Joey Adams, The Curtain Never Falls. The protagonist of the story is a young stand-up comic named Jackie Mason (perhaps inspiring the stage name of the real-life Jackie Mason, born Yacov Moshe Maza, who would devote a few pages to “chopped liver” in his 1990 book, How to Speak Jewish). In the novel, when a showgirl feels like that Jackie isn’t paying her enough attention, she says, “You’ve been nice enough, but what am I, chopped liver or something?” Jackie responds, “Are you kiddin’? You’re the sexiest-looking thing up here. But you always seemed interested in all the shmoes.”

Another variation on the theme was used by Jimmy Durante on his television show in 1954, according to Jonathan Lighter’s Historical Dictionary of American Slang: “Now that ain’t chopped liver.” That follows the pattern of earlier expressions like “That ain’t peanuts,” “That ain’t persimmons,” and “That ain’t hay.” Jonathon Green, in his Green’s Dictionary of Slang, takes the “persimmons” version all the way back to 1851 in American usage.

When William Safire asked the lexicographer Sol Steinmetz about the “chopped liver” expression in a 1998 New York Times “On Language” column, Steinmetz offered, “Chopped liver is merely an appetizer or side dish, not as important as chicken soup or gefilte fish. Hence it was often used among Jewish comedians in the Borscht Belt as a humorous metaphor for something or someone insignificant.”

Chopped chicken liver might seem even more insignificant, reinforced by the fact that “chicken liver” carries its own set of pejorative connotations having to do with meekness and cowardice. In 1968, syndicated columnist Jim Bishop wrote about seeing Don Rickles perform at a Miami Beach nightclub: Rickles, with his caustic insult comedy, “chopped the audience like chicken liver.”

When the comic actor James Coco achieved fame as a frequent “Tonight Show” guest in 1972, he told The Philadelphia Inquirer that he was shocked not to be recognized in Rome. “I would walk down the street and nobody looked at me,” Coco said. “I thought, ‘What am I? Chopped chicken liver?” That same line, with “chopped chicken liver,” was also used by Tony Curtis playing a flashy Hollywood producer in the 1980 mystery movie The Mirror Crack’d. And in 1991, Henry Winkler said the same thing in an interview with The Chicago Tribune about a TV movie he was starring in.

The Bloomberg-style version, with “chopped” elided, also has some precedence. For instance, when The New York Times creating new titles of “senior writer” and “senior photographer” for a select group of staffers in 1990, Chicago Tribune media columnist James Warren wrote, “Picking any such group in a workplace would bring grousing. People left out wonder, ‘Am I chicken liver?’”

One example strikes even closer to home. In 2002, when Bloomberg was mayor of New York, he faced contentious contract negotiations with the United Federation of Teachers. The union’s president, Randi Weingarten, told The New York Post that the teachers didn’t want to strike, “but she said they feel like ‘chicken liver’ for being without a contract for 16 months and facing a second year of budget cuts.”

After getting eviscerated at Wednesday’s debate, Bloomberg may know what that feels like too.