At a trial beginning this week in Dallas that pits onetime Texas billionaire Sam Wyly and his wife against the Internal Revenue System, Texas lawyers will likely play pivotal roles on the witness stand.

Both the IRS and the Wylys, for instance, have put on their witness lists William Cousins, a partner in Dallas’ Meadows, Collier, Reed, Cousins, Crouch & Ungerman, who advised the Wylys. Both sides have also said they might show the jury transcripts of prior testimony of Michael French, a former partner in Dallas’ Jackson Walker.