Stanford Law School professor Deborah Rhode, a former special counsel to the House Judiciary Committee, said the Mitchell Report, conducted by former Senate majority leader George Mitchell, has credibility with Congress. She said contradictory testimony — such as Clemens' if he repeats earlier denials — would logically be referred for criminal investigation.

"It doesn't cost Congress anything to make a referral," Rhode said.

But she and others agreed that if a referral is made, any actual indictment or action by the Justice Department is unlikely if the situation remains a "he said/he said" accusation.