For the third thread, let's take a look at another common way of how the law evolves - when social values change to such a degree that the law has to follow suit. It may result in a slower rate of change, but it is change nonetheless.

Does the case Plessy v. Ferguson ring a bell for some of you? What was that case about? What was the specific constitutional challenge involved? (What does that mean - when someone challenges the constitutionality of a law - is it more than simply saying "I don't like that law. That law is bad?")