CEI accused Michael Mann of various things, and Mann sued for defamation. Now there’s some progress on the case.
“The first line of defense you as a defendant can use in a defamation case, when you’ve done a good job, is that what you’ve said is true. They don’t even attempt to make that argument”
http://rabett.blogspot.fi/2017/01/the-most-important-political-takeaway.html