What's the point of having the source maintain anonymity for "normal" non-secret stuff? There's no point in not naming your source unless it's damaging secret stuff--in which case call your source "anonymous" instead of "a senior administration official" or "party staffers".

For anything else, if your sources remain unnamed, there's no way for the public to corroborate your assertions, and it's not "news" anymore, it's "opinion"...