Bush from the debate:

Another example would be the Dred Scott case, which is where judges years ago said that the Constitution allowed slavery because of personal property rights. That's personal opinion. That's not what the Constitution says. The Constitution of the United States says we're all - you know, it doesn't say that. It doesn't speak to the equality of America.

We already knew that Bush is not too bright, but now we know that he thinks that the US constitution of 1857, the date when the Dred Scott case was decided, did not allow slavery.