Walton warned the lawyers that Issa might "bury your client."
And they won't get the chance to call him after Walton's ruling Monday.
Issa is chairman of the House Oversight and Government Reform Committee, the panel that Clemens allegedly lied to in 2008 when he denied taking performance-enhancing drugs.
Issa, a California Republican, wasn't chairman at the time. He had criticized the committee for holding the hearing on drugs in baseball -- but also said he didn't doubt that Clemens had perjured himself.