Angry US senators said a special prosecutor should investigate misconduct at the Justice Department, accusing attorney general Alberto Gonzales of deceit over prosecutor sackings and President George Bush's eavesdropping programme.
Democrats and Republicans alike attacked Mr Gonzales in four hours of testimony as he denied trying, as White House counsel in 2004, to pressure a sick predecessor into approving an anti-terror programme that the Justice Department then viewed as illegal.
Mr Gonzales, alternately appearing weary and angry, promised again to remain in his job even as senators told him they thought he was unqualified to stay.
Senator Russ Feingold
He would not answer numerous questions, including whether the Bush administration would bar its US attorneys from pursuing contempt charges against current and former White House officials who have defied congressional subpoenas for their testimony.
"It's hard to see anything but a pattern of intentionally misleading Congress again and again," Senator Russ Feingold told Mr Gonzales during the often-bitter Senate Judiciary Committee hearing. "Shouldn't the attorney general of the US meet a higher standard?"
"Obviously, there have been instances where I have not met that standard, and I've tried to correct that," Mr Gonzales answered.
The hearing rekindled a political furore that began with last year's sackings of nine US attorneys and led to disclosure of a Justice Department hiring process that favoured Republican loyalists.
Mr Gonzales has Mr Bush's support, despite repeated calls for his resignation and questions about his role in a hospital room confrontation with then-attorney general John Ashcroft over whether to renew a classified, but potentially illegal national security programme.