[ClearCase_guy]

But Obama erred by looking backward -- as far back as slavery. What does slavery have to do with the price of milk at the grocery store?

Is there a Godwin's Law equivalent for slavery? You know, the first guy to mention slavery in a discussion about race automatically loses the argument?

[ArrogantBustard]

Is there a Godwin's Law equivalent for slavery?

There is, now. You just articulated it:

The first guy to mention slavery in a discussion about race automatically loses the argument.

I hereby dub this the ClearCase Principle.

If you wish to refine your statement of it, this would be a good opportunity.