Sorry, but if you insist on that, you didn't understand the concept: Any certificate signed (transitively) by a root CA is valid. There are no distinctions between more or less valid certificates; they are either valid or invalid. Even if you talk about a single CA, what do you mean? A name of a CA, or one specific certificate of a CA? Over time one CA may have more than one certificate.
Sorry, you are wrong. I suggest you think about this for a while until you realize why blindly trusting any cert issues by any CA is not a good idea.
--Quanah -- Quanah Gibson-Mount Architect - Server Zimbra, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration