Where did the phrase "You're full of malarkey" come from?

The phrase you're full of malarkey meaning you are full of nonsense or you are lying comes from early 20th century American slang with Irish-American roots and became a popular idiom. The word malarkey first appeared in American English in 1922 in the cartoons and writings of Thomas Aloysius Dorgan, known as Tad Dorgan, a famous sports cartoonist for the New York Evening Journal who is credited with popularizing many slang terms like 23 skidoo and hot dog. Dorgan used malarkey to mean nonsense or bunk. Etymologists trace malarkey to the Irish surname Mullarkey or Malarkey, which was used as a stereotypical Irish name and became associated with blarney, meaning exaggerated talk or tall tales, in Irish-American communities in New York and Boston in the 1920s. The phrase you're full of malarkey follows the pattern of you're full of baloney or you're full of bunk, which were common ways to accuse someone of talking nonsense without using profanity, making it acceptable for newspapers, radio, and polite conversation. It was used in vaudeville, movies, and politics throughout the mid-20th century. The phrase gained major renewed fame when President Joe Biden, who is of Irish descent, adopted it as a signature catchphrase during his political career, frequently telling audiences you're full of malarkey or that's a bunch of malarkey to dismiss false claims.