From the article you pointed me to:
---"If Matt Cooper is going to jail to protect a source," Mr. Luskin told The Journal, "it's not Karl he's protecting."---
That quote is specific to Cooper. There is no mention of Miller. If Rove was Miller's source, why didn't Luskin mention her in the quote. I still believe that Miller has another source, one that the Times does not want to reveal. Why is the Times stone-walling. Who are they protecting?
I don't know why Luskin didn't mention Miller. It could be, like you think, that Rove is not her source. Alternatively, since we don't have the full context Luskin's quote, one possibility is that the question or the conversation was specifically about Cooper. An attorney would be normally be careful not to answer more than was asked.
You are right that Miller might have a different source. I'm just saying that just because Cooper got a release that doesn't necessarily mean that Miller has a different source. She could have multiple sources, even. If Rove gave her a release, but Scooter Libby did not then she still can't talk.
I still believe that Miller has another source, one that the Times does not want to reveal. Why is the Times stone-walling. Who are they protecting?
The Times does not want to reveal any secret sources. If they reveal the name of a source, they are less likely to get secret information next time they talk to someone.
The real question is why Time Magazine released the emails between Cooper and his editor. Time burned Rove. Why would anyone ever talk to a Time reporter again?