| It doesn't stop|
at the water's edge
Moonbat is a snarl word referring to anyone whom the speaker considers unreasonably far to the left, analogous to "wingnut." The word's definition has undergone a confusing bifurcation: conservatives use it to describe pretty much any moderates and liberals, and liberals use it to refer to batshittery within their own camp — not just extreme left-wingers, but also cranks and conspiracy theorists.
 According to conservative wingnuts
- George Monbiot – geddit?! It sounds like his surname, and he's a leftie!
- Secular Humanists
- Social democrats
- People who are Left-Wing, Center-Left and some Centrists.
- People who don't believe in Young Earth Creationism or Intelligent Design.
- People who are not evangelical Christians.
- People who acknowledge the existence of global warming and Climate change.
- People who believe that apply environmental laws are good and necessary.
- People who do not (or do, depending on who's in power) support the Iraq War.
- People who do not (or do, depending on who's in power) wish to invade Iran.
- People who believe gays should have equal rights, or at least that they shouldn't be stoned to death.
- People who do not want to live in a theocracy.
- People who get laid before marriage.
- People who criticize Ann Coulter, Jerry Falwell, Pat Robertson etc.
- People who want healthcare to be more widely accessible.
- People who are not unabashedly racist and sexist
- People who are not free-market capitalists
- Cindy 'Ultra MK' McKenzie
 According to liberals
The far-left-wing sort of moonbats are the closest analogies to wingnuts. In North America, the former is much more rare than the latter, probably due to shifts to the political right since the late 20th century, but where they do exist it's usually of a more hard green bent as opposed to an economic one (e.g. a communist). The more extreme buffoons of the anti-imperialism movement, like Ward Churchill, also contribute to America's moonbat population.
One reliable heuristic when separating moonbats from more rational lefties is their categorical opposition to everything the U.S. does overseas, to a degree unwarranted by skepticism. For example, Muammar Gaddafi kills protesters? Serb militias ethnically cleanse Bosnia and Kosovo? All of this is protested vigorously... until the U.S. and its allies move to intervene against the offenders, at which point genuine moonbats will often perform an instantaneous 180 and defend the repressive regime that they had previously loathed. It is rational to criticize a war by saying that it is killing more people than it was meant to save, causing major regional instability, or that it will generate unwanted blowback—but when one turns to sensationalism, platitudes, and name-calling, one has crossed into moonbat territory.
Cranks in general — alties, conspiracy theorists, anti-vaxxers, anti-GMO crusaders, and especially the New Age crowd — are often classified as moonbats, unless their ideas are intertwined with a right-wing and/or racist ideology, in which case the wingnut label is more appropriate. Examples of cranky moonbats are David Icke and Vani Hari. Alex Jones, contrariwise, is a wingnut due to his wacky theories fueling a Christian fundamentalist agenda.
A final subcategory of moonbats generally leans left while holding a few views more typical of wingnuts, ushering in horseshoe theory comparisons. Cathy Brennan's extreme transphobia and Sam Harris's support for racial profiling or torture (and specifically of Khalid Sheik Mohammad) fall in this category.
 Other usage
In the last few years, the term "moonbat" has also come to refer to those individuals who subscribe to conspiracy theories regardless of political affiliation. Typically, such individuals have little regard for rational discourse, lack the ability to provide credible sources to support their arguments, and fail to demonstrate an elementary understanding of the fields they make claims about.
Most likely, the term has come to such an understanding due to the "screeching" such people do about a given conspiracy theory while unable to intelligently convey a legitimate reason for accepting it as fact.
 See also
- Discussion of the origin of the term (conservative William Safire in The New York Times)
- Blogs 4 Brownback
- "Myrtle the Moonbat". 6 September 2006.