Libby would have to say "Cheney told me to shop Plame to reporters" whereas his current defense is either he forgot about being told by other officials (including Cheney) or the reporters are lying and actually told him. Even if he says Cheney told him and gets Cheney on the stand, I don't see how that hurts Cheney unless he draws Cheney in as part of a conspiracy. OTOH, the public damage from media spin following Cheney's testimony could be severe.
Whoever the background people are pushing this agenda they fully realize that Libby is a nothing, just another political hack. A minnow if you will. They are using Libby like John Dean of old.
"... or the reporters are lying ..."
Now there's a concept!