The 21st century version of a "Yellow dog Democrat". The term came about following the election of Donald Trump, when left-wingers began proclaiming that they would vote for Adolf Hitler if he ran against Trump in the following election (despite the fact that Trump apparently IS Hitler). This admission that they would happily vote for Hitler so long as he ran as a Democrat led people to 'update' the term "Yellow dog Democrat" to reflect the current state of American (or, more specifically, left-wing) politics.
Person A: I would vote for a Hitler/Biden ticket if it means getting Trump out of office!
Person B: Do you even hear yourself, you idiotic Hitler Democrat.
Person B: Do you even hear yourself, you idiotic Hitler Democrat.
by Saudades October 10, 2020