Godwin's Law is the observation that eventually in a long discussion, usually online, someone will draw a comparison between the opposition and Nazi Germany. Such comparisons will generally come from the side with the weaker arguments.
It seems that in our political debates, the Nazi comparison is made less and less as years go by (maybe because most poeple alive today have no direct memory of the Holocaust), but other comparisons are being made. In the past 10 years, I have heard one side or another in political debates compared to the Taliban, and most recently to terrorists in general. This is not limited to politics, either; I have heard such comparisons made in debates in the Presbyterian Church.
Such comparisons do little to further civil debate, yet they provide stark sound bites for the prime time news shows. And I suspect that they play more to political extremes than to the larger center that is the key to winning the public debate.