Paul — who has strongly opposed the impeachment proceedings against President Donald Trump — has been floating the alleged whistleblower’s name in media interviews for months.

But Roberts signaled to GOP senators on Tuesday that he wouldn’t allow the whistleblower’s name to be mentioned during the question-and-answer session that started the next day, the sources. Roberts was allowed to screen senators’ questions before they were submitted for reading on the Senate floor, the sources noted.

Senate Majority Leader Mitch McConnell (R-Ky.) and other top Republicans are also discouraging disclosure of the whistleblower’s identity as well. Paul has submitted at least one question with the name of a person believed to be the whistleblower, although it was rejected. Sen. Mike Lee (R-Utah) composed and asked a question regarding the whistleblower earlier Wednesday that tiptoed around identifying the source who essentially sparked the House impeachment drive.