Then why not just bring up Dred Scott case in the 1800s or something to show you have a little knowledge in the area?
You'll have to ask that question to Sarah Palin. I can't answer it for her. If you choose to believe that refusing to answer the question indicates lack of knowledge, I can't help you.
For her part, she's admitted she didn't handle it very well. Every question was a loaded, trap question and she got pissed. If I was a POTUS or VP candidate being shown no respect like that, I probably would have walked off the set and totally blown my election chances...LOL.
The Supreme Court question was a prime example of what was happening on that set..."Name a SCOTUS case you disagree with, but you can't discuss Roe and you can't discuss Kelo (which would make Sarah Palin look good). Hell, Couric might as well have had a neon sign on the set that said, "It's a TRAP!"...LOL.