You said you knew what it is, and now you're saying the complexity is "news" to you, and you admit you yourself only knew a part of it. I'm confused which is driving your answers but it's not important.

It seems like she didn't have a "clue" to people who constantly find something about her to criticize. She asked it the right way, proving she does know how complex it is before you answer it.

I would say the same regardless of who it is. I wouldn't expect Obama to say "Oh, well, I think....". All he could say is "I think it means....". Everyone who is familar with the term knows it's open to interpretation and most people can't agree on its definition. It's a lot of broad policies, not a single one.

I'm sure Biden's debate coach will get him up to speed on it before the debates so he can also talk about the different facets of it.

Like Quimba said, people should focus on the issues.