In the form of Micheal Mann (of the discredited hockey stick) vs Mark Levin. Mann sued Levin (actually both the National Review and Competitive Enterprise Institute that Levin put forth his opinions via) for defamatory statements and fraud due to Levin calling Mann a fraud. Of course Mann put forward in his initial press release about the suit that he was awarded the Nobel peace prize along with Gore...a blatant lie. Levin countersued for $10m and now it's going through the courts. Since Levin is counter suing, all of Mann's work is subject to criticism.