Godwin's Law (also known as Godwin's Rule of Nazi Analogies or Godwin's Law of Nazi Analogies) is a humorous observation made by Mike Godwin in 1990 which has become an Internet adage. It states: "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1."-Wikipedia
Godwin's Law doesn't just apply to the Internet anymore (to the extent that it ever did). While not a logical fallacy per se (though it has given rise to the term "reductio ad Hitlerum"), it is a pretty good indicator that your erstwhile debate opponent is running short of cogent arguments - colloquially, the debate can be said to have "jumped the shark". Let's look at several contentious debates in society - or at least, contentious in American society.
First, one of the oldest: abortion. Godwin's Law has been a regular feature of this debate from the beginning. Just Google "abortion holocaust", and you'll find sites such as AntiAbortionSigns.Com (Warning: graphic images). A group that is (in)famous for using this comparison is the Genocide Awareness Project, which is run by the innocuous-sounding Centre for Bioethical Reform. I suppose technically this doesn't constitute Godwin's Law, but it's only about one degree separated.
Second, the evolution-creationism debate. One need look no further than Ben Stein's recent abortion (no pun intended) of a film Expelled: No Intelligence Allowed. In it, an explicit claim is made that Darwinism led to Nazism and, by extension, the Holocaust. Needless to say, this claim is ridiculous and tendentious in the extreme.
Third, the anti-vaccination movement. As a recent post over at Age of Autism demonstrated, now people advocating vaccinations are being compared to baby-eating monsters. Again, strictly speaking this isn't an instance of Godwin's Law at work, but it didn't take long for commenters over at AoA to invoke the Holocaust in comparison:
It's a horrible image. So are the images of boxcar loads of men, women and children going to Dachau, or the image of the napalm scorched Vietnamese girl running down the road. Obviously reality is horrifying. Sins of omission do just as much damage.
There's also no shortage of other people invoking comparisons between vaccinations and Nazi Germany.
Fourth, the health care debate in the United States. Numerous pundits and countless tea-baggers have invoked comparisons between Obama and Hitler, but it takes a special kind of stupid to compare your opponents to Nazis because they want to ensure that everyone has access to health care. Laura Ingraham recently provided a particularly good example of this, for which Jon Stewart promptly took her to task.
Fifth, and perhaps the biggest stretch of all, is the anthropogenic global warming debate. A recent post at the blog BigGovernment.com blames the "Neo-progressive movement" for promoting AGW, invoking comparisons to - yup, you guessed it - eugenics. Then there was Glenn Beck's thinly-veiled Godwin when he said that America was "an Axis country" when it came to climate change. Or noted wingnut Lord Monckton calling young climate change activists "Hitler youth" (@2:52). Or Republican congressman James Sensenbrenner accusing scientists of engaging in "scientific fascism". On the other side of the political spectrum (although these days, apparently it's the same side), we have a Wall Street Journal editorial calling climate scientists "closet Stalinists".
To be fair, I should also address the usage of the term "climate denier" by AGW proponents. I don't think this qualifies as a Godwin, because usage of the term is not (so far as I have experienced) intended to imply that the person is a Nazi. There is, no doubt an unavoidable connotation by association with the term "Holocaust denier", but it seems to me that the analogy is intended to be epistemological, not political. That is, a climate denier is someone who steadfastly refuses to look at the available evidence and will go through all manner of logical contortions and cognitive dissonance to avoid being confronted by historical fact. That doesn't make someone a Nazi - that just makes them willfully ignorant.
Finally, the icing on the cake is the rather pathetic attempt at historical revisionism by the American right to cast Nazism as a liberal (and by "liberal", they mean "leftist") movement. The most high-profile example of this is Jonah Goldberg's book Liberal Fascism: The Secret History of the American Left, From Mussolini to the Politics of Meaning, an exercise in guilt by association (e.g., Hitler was a vegetarian, many liberals are vegetarians, therefore liberals are like Hitler). There's a comprehensive review and series of rebuttals of this revisionist nonsense over at Orcinus.
I forgot one of the big topics: gun control (My personal views on this subject are somewhat nuanced and may be the subject of a future post). Perhaps nowhere is the Godwin tactic more often used than in gun control arguments (in fact, it's one of the two topics specifically mentioned in the Godwin FAQ, the other being abortion). Inevitably, the argument is made that any attempts at gun registration or gun control are the first step towards a Nazi/totalitarian government. People will try to lamely argue that the Nazis had to disarm the Jews before they could carry out their "final solution". This argument is so ridiculous that even the very pro-gun site GunCite.Com says:
The simple conclusion is that there are no lessons about the efficacy of gun control to be learned from the Germany of the first half of this century. It is all too easy to forget the seductive allure that fascism presented to all the West, bogged down in economic and social morass. What must be remembered is that the Nazis were master manipulators of popular emotion and sentiment, and were disdainful of people thinking for themselves. There is the danger to which we should pay great heed. Not fanciful stories about Nazi's seizing guns.
I also forgot another whopper: atheism. This topic would have to vie with gun control for most frequent Godwinning. I suspect there isn't a discussion concerning atheism anywhere on the Internet where someone hasn't pulled the "Oh yeah, well Hitler was an atheist" card. Of course, Hitler was no such thing. However, this topic also probably requires corollaries to Godwin's Law involving Mao, Stalin, and Pol Pot.