Today in History —> On this day in 1870 – A political cartoon for the first time symbolizes the Democratic Party with a donkey (“A Live Jackass Kicking a Dead Lion” by Thomas Nast for Harper’s Weekly).
Here’s the cartoon. Andrew Jackson’s enemies twisted his name to “jackass” as a term of ridicule regarding a stupid and stubborn animal. However, the Democrats liked the common-man implications and picked it up too, therefore the image persisted and evolved.