Ummm, i think it depends on what the teacher wants and what the question ask (ie, list all the possible claims and defenses for X). If it could possibly apply, i think its good to include it. But if you failed to include something that was only slightly related, its probably not worth that much so I don't think you should feel too bad.
In light of my mistake and also my frequent contribution, does anyone think it might be a good idea to get in touch with the professor and explain to her what I did wrong, that I am not a total dunce when it comes to this material, that I am not deserving of a D or F? What do you guys think?