Nazis, Race and Political Speech

Two very different politicians got into some hot water this week for being the first two, post-Tucson, to say something that strikes others as outrageous.
Rep. Steve Cohen of Tennessee said that the Republican lies about the health care law followed the same pattern of propaganda used by Joseph Goebbels, the Nazi propaganda minister.
Then, former Senator and likely president candidate Rick Santorum said that he was surprised President Obama was pro-choice because, as a black man, he should be able to understand that if the Constitution or the courts interpreting the Constitution deny personhood to persons, the Constitution is wrong or the courts are wrong.
Cohen - and all politicians - should know by now to cut with the Nazi analogies. The evil of the Nazi regime was so grotesque, its lies so intertwined with the evil produced by the regime, that comparisons are always wrong-headed and offensive. When you bring up the Nazis, you have just lost your argument. Except, of course, when talking about neo-Nazis, and there are some of those.
Santorum, who is not someone I agree with on much of anything, was making a different argument and, whether you agree with it or not, there was nothing racist about his argument. Essentially, he was comparing Roe v. Wade with the Dred Scott decision, insofar as both ruled that some persons were not legally congizable as such under the Constitution. My only fault with Santorum is that he singled out the President, whose forebears were not slaves, they were Nigerians, so it is hard to see why Obama himself should have a special burden regarding Dred Scott.
Of course, the problem with Santorum's argument is that the Constitution acknowledges rights of citizens, those "born" in the United States or naturalized. Which is why it would take a constitutional amendment conferring the rights of citizenship on the unborn to undo Roe. I would be delighted to support such an amendment, but there are many of my fellow Americans who do not look at a zygote and think "citizen." I think they are wrong, but they are not evil the way the justices who decided the Dred Scott case were evil. There was no denying that blacks were persons and claims to that effect had long been abandoned. So, while I do not think the analogy is offensive as some do, I also do not think it works.
Final score: Cohen gets an "F" and Santorum gets a "C-".