WASHINGTON (CNN) -- The judge and attorneys in the Lewis "Scooter" Libby case slogged through more potential jurors Thursday to reach 30 qualified out of a necessary 36, prompting the judge to hope for better results when jury selection resumes Monday.

In three days of interviews, U.S. District Judge Reggie Walton and the trial attorneys have disqualified 19 potential jurors, many after expressing negative beliefs about the Bush administration, which could lead to bias at the trial.

"It took all day to qualify six jurors," Walton said at the close of the day. "I hope that's not the case Monday."

Walton and the attorneys must assemble a pool of 36 qualified people; from that group they will pick 12 jurors and four alternates. The judge had hoped to begin the trial Monday with opening statements; now, he said, jury instructions and those statements will come Tuesday.

Libby resigned as Vice President Dick Cheney's chief of staff after his October 2005 indictment by a federal grand jury probing the 2003 disclosure that the wife of an Iraq war critic was a CIA officer. Cheney is a potential witness.

Libby is charged with perjury, obstruction of justice and making false statements to federal agents investigating the leak.