Moonbat can also be used as an adjective, e.g. a moonbat professor. According to the Wikipedia entry for moonbat, the word was coined in 2002 by the Editor of Samizdata, Perry de Havilland, and was a variation on the name of radical British activist and columnist George Monbiot.
Originally, the term "moonbat" was intended to be more politically neutral, and described wackos on the left and the right, but it quickly acquired its current usage of being applied almost exclusively to those on the left.
The term also references the moon much in the same way that "lunatic" refers to the insanity-causing powers of the full moon (luna = moon). Bloggers occasionally analyze the behavior patterns of various moonbat "species" as if they were actual animals, and even give them satirical Linnaean taxonomical names, such as "moonbattus berkeleyensis".
The entry in the Samizdata glossary indicates that Perry originally coined the full phrase "barking moonbat"; apparently "moonbat" is just a subsequent shortened version of "barking moonbat," rather than being a pre-existing term that was lengthened to barking moonbat.
Worker #2 "Yeah, all eight of them."
Worker #1 "Man, they need to get real jobs."
Moonbat McWacky: Actually, the Mercury Dime predates Fascism by several years, and the same symbol can be found in the Oval Office, Congress, and the Lincoln Memorial.
Jones: Good God, Moonbat, do you know what that means? Fascists have been trying to take over this country... since before they even existed!
While no doubt extremists do exist, the casual disregard for alternative viewpoints, and the implied disdain for Constitutional dissent which simmers beneath its surface, is far more disturbing to the average political theorist than any Leftist dogma, extremist or otherwise, yet to surface.
"Moon" refers to Earth's primary natural sattelite, which humans visited for a brief period thanks to a massive liberal spending program. The scientific and technological benefits of the Apollo Project were immense, and would have been far greater if the program had not been killed by a right-wing administration that wanted to spend that money on a futile foreign war. Thus, the Moon is, like bats, symbolic of liberalism and all the benefits it brings to a culture, and naturally will be an object of hatred and fear to the Right.
Combine the two and you get "Moonbat"; environmental good sense, scientific curiosity, prosperity for all and the triumph of knowledge over traditional superstition. In short, all the things that enemies of civilization like Osama bin Laden and Pat Robertson hate most.
convenience. A caller to the Howie Carr radio show summed
it up as "These people wear winter clothes in the summer".
Characterized by men in ponytails, sandals with socks,
and 1.20.09 Bush's Last Day bumperstickers. Often seen
at global warming marches that take place during snowstorms.