Term invented in Soviet Russia to describe people who blindly supported the likes of Lenin and Stalin while they committed atrocity after atrocity.

Today, it refers to brainwashed [liberal]s and [leftist]s the world over (usually college students that aren't necessarily idiots, but just misinformed, naive, and ignorant of facts due to being indoctrinated with liberal/socialist propaganda through their public education) who believe that George W. Bush has committed more crimes against humanity than leftist darlings like Saddam Hussain, Yasser Arafat, and Osama Bin Laden, and still defend Communism, the cause of over 100 million deaths to this day.

See also, [idiotarian]
> Hundreds of useful idiots gathered at their college campus to burn American flags, pass out Communist pamphlets that apologize for Stalin and Mao, and to pledge support to their hero, Saddam Hussain.
> Useful idiots need to be shown the facts, mainly that the United States and Israel are the greatest defenders of freedom and justice in the world. Until then, rational people can have fun laughing at their ignorance.