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 1989 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." In other words, Godwin put forth the hyperbolic observation that, given enough time, in any online discussion—regardless of topic or scope— someone inevitably criticizes some point made in the discussion by comparing it to beliefs held by Hitler and the Nazis.
Most primary sources make it pretty obvious that Hitler was a Catholic. He references "Divine Providence" and "Our Lord Jesus Christ" and Jesus' "struggle" against the "Jewish poison" all throughout his many publicly documented speeches. This is what people will tend to refer to when they say that Hitler was obviously a Catholic.
But there are also Christians out there who insist that Hitler was "secretly" an atheist. The primary source for this conspiracy theory is "Hitler's Table Talk," a series of statements consisting of comments Hitler supposedly made "off-the-record," that were recorded and published at a later date by what are said to be first-hand accounts --- comments that supposedly revealed his "anti-Christian" or at least "anti-religious" motivations.
Now for reasons of brevity, I won't go into the actual truth or falsehood of either of these claims. What I want to discuss here is the reasoning behind these claims --- the points they were invoked to defend against, and their effectiveness toward that end.
Hitler is almost unanimously mentioned as an "atheist" in circles where fundamentalist Christians want to equivocate between "science" or "evolution" or "atheism" and genocide. Ben Stein has famously compared evolution to the Nazis, saying that "science leads you to killing people." Hitler is almost always trogged out to support this accusation --- the implied sentiment is, "Hitler is what happens when you accept evolution."
So when, say, an atheist brings up Hitler's public mention of Christianity, God, Jesus, Divine Providence, and the Christian roots of anti-Semitism, or the fact that the buckle of each Nazi uniform read Gott Mit Uns (God With Us) and asks the theist, "what is the explanation for that if Hitler was an atheist?" The response will be, "Hitler was secretly an atheist, but he used Christianity in order to deceive the public so he could carry out his master 'Darwinist' plan."
This is where I want to come in and say: even if we assume that this accusation is 100% true --- that "Hitler was a secret atheist using Christianity as a front for his conspiracy to 'commit Darwinism'" is a 100% accurate reflection of reality --- it remains true that Hitler would not have been able to do even that if there did not exist a ready and willing followership of Christians ready to accept this "front."
Seriously, stop and think about that for just a few seconds: simply by accepting the idea that Hitler could successfully use Christianity as a front implies that there are a large number of Christians who would agree with such a front. The very idea that "using Christianity as a front" for the Holocaust would have any degree of success whatsoever can only be true if a large amount of Christians are willing to support it. What would have been the use of Hitler "pretending to be Christian" if Christians everywhere had unanimously spoken against the Holocaust and the Jewish genocide? The very idea that such people could be exploited hints at the notion that the ideas commonly attributed to Hitler himself (such as genocidal anti-Semitism) found ground for common acceptance within the Christian populace.
If the Nazis had all been atheists, or even just openly anti-Christian, then there would have been no need for Hitler to "feign Christianity" in order to "exploit" the atheist populace. He would just say, "Hey, we're all atheists, let's take over the world and commit genocide!" There would be no need for such a "front" as Christianity. The idea that such a front would even be necessary insists that Christianity was, in fact, the dominating mindset within Nazi Germany.
Before I make my closing point, I want to say that in casual conversation (or in internet debate), I make it a point not to bring Adolph Hitler and the Nazis up as a counterpoint to anything not already pertaining to Nazism, as to me it reeks of reductio ad absurdum. I personally do not believe that "Christianity made Hitler do it," or that "evolution/atheism made Hitler do it." I have another reason entirely why I believe the Nazi efforts were successful to the extent that they are, even if Hitler's ideology was ultimately idiosyncratic (which it clearly was not). So do not read this as an accusation of either party in that respect.
I believe that regimes like the Nazis (or the current regime in North Korea) are possible not because of "evolution," or even because of "Christianity," specifically. It is my understanding that such regimes come to power because of the effect that irrational faith has on people. Keeping in mind that there are two kinds of faith --- faith established through testing experience, such as the faith you have in a friend or certain family member; and blind faith, the kind we talk about when we say "leap of faith," the kind of faith that people assert to believe in God or in ideas that have not been demonstrated or tested --- I am talking about the latter of the two, blind faith.
For if you take the position that is implied by the Christian defense against Hitler --- that the German masses were really good-hearted, but ultimately unwitting, victims to Hitler's propaganda machine, and were simply being used by Hitler under the guise of "Christianity" --- then it follows that *something* made them believe in Hitler and his cause, in spite of its asserted "deviance" from accepted Christian norms. Today's Christians assert that there is simply NO WAY WHATSOEVER to justify anti-Semitic genocide using the Bible or Christian beliefs, so it cannot be a reason derived from the beliefs themselves (otherwise the entire point of this defense would be useless; even if Hitler WAS using Christians, it wouldn't matter because their beliefs would've overlapped with his anyway, rendering this justification self-defeating). So from a Christian perspective, it couldn't be a rational position; a critical angle would have lead them to oppose Hitler.
So accepting the offered Christian defense against Hitler, and removing the possibility for a skeptical approach to Hitler's ideas on behalf of the Christians serving under him, the only possibility that remains (and that can account for such widespread, zealous and unquestioning support in spite of supposedly "differing" religious ideas) is blind faith. Hero worship. Savior mentality. Hitler was the "saving grace" of the German state and economy; therefore his ideas were perfect and not to be questioned.
Let me say in closing that it is not my intent here to argue from scratch that "the Nazis were motivated by Christianity," or to say that "Christianity inherently leads to Nazism and genocide;" I'm not quite as shameless as some of my Christian contemporaries that I would make such a bold and crass blanket statement. However, if we follow the line of reasoning, used by Christians who invoke this argument against atheists, to its logical extreme, then we will see that indeed, the Nazi regime could not have happened without Christianity.
Once again, I'll say it: This is not my argument, this is my response to the arguments made by Christians that evolution or atheism necessarily leads to Hitlerian/Nazi ideology.