Thumbs Down to Governor Bill Clements for not know-ing when to keep his mouth shut. At a recent news conference, the governor coquettishly implied that, yes, he did have knowledge that Dallas millionaire H. Ross Perot had been contacted by the State Department concerning the Iranian hostage situation. For further details, the governor said, call Perot. Contacted by the press, Perot said a) he hadn’t been in contact with State, and b) if he had, he wouldn’t be talking about it to anyone. Told of the governor’s comments, the industrialist said tersely, “That’s his problem.” We agree. Whether Perot has been in contact with federal authorities about the situation or not, Governor Clements has no business talking about it; such airing of potentially sensitive information can only rnake a volatile situation worse. We suggest the governor stick to commenting on matters he’s authorized to, like the Campeche Bay oil slick. On second thought, maybe he’d better keep quiet about that too.