WASHINGTON A top aide to Attorney General Alberto Gonzales resigned over the firing of U.S. prosecutors and Gonzales pledged on Tuesday to get to the bottom of a growing flap that has embarrassed the White House and prompted calls for him to step down.
Democrats in the U.S. Congress vowed to quickly expand their investigation into whether the dismissal of eight prosecutors, some of whom had been criticized by Republicans, was politically motivated interference by the White House.
The Senate Judiciary Committee and a House Judiciary subcommittee held hearings on the dismissals last week, and Democratic leaders said there would soon be more and, if needed, subpoenas served to require witnesses to testify.
"I acknowledge that mistakes were made here. I accept that responsibility," Gonzales told a brief news conference at the Justice Department.
"My pledge to the American people is to find out what went wrong here, to assess accountability and to make improvements so the mistakes that occurred in this instance do not occur again in the future," he said.
U.S. attorneys are appointed by the president, who can remove them from office for any reason. President George W. Bush believes Gonzales made the right decision in firing the eight U.S. attorneys, said White House counselor Dan Bartlett.
"The president has all the confidence in the world in Alberto Gonzales," Bartlett told reporters covering Bush in Merida, Mexico.
On Democratic calls to question Karl Rove or other White House advisers, Bartlett said, "I find it highly unlikely that a member of the White House staff would testify to these matters."
Kyle Sampson, the chief of staff to Gonzales, resigned, effective immediately, after acknowledging he did not tell other Justice Department officials earlier about the extent of his communications with the White House about firing the prosecutors.
As a result, the department provided incomplete information to lawmakers, Gonzales said.
Administration officials said then-White House counsel Harriet Miers had suggested to Sampson two years ago that the Justice Department fire all of the nation's 93 U.S. attorneys.
That was immediately rejected. "I felt that it was a bad idea," Gonzales said. The White House approved the idea of dismissing a smaller group, the officials said.
The eight prosecutors were fired last year after Bush spoke to Gonzales about complaints that some of them were not energetically pursuing voter-fraud investigations, White House spokeswoman Dana Perino said.
Newly released e-mails and other documents showed much closer coordination between the White House and the Justice Department on how to carry out the firings than what department officials had previously acknowledged.
Senate Democratic leader Harry Reid of Nevada joined other lawmakers in calling for Gonzales to leave and said, "It appears he's over his head in this job."
Sen. Charles Schumer, a New York Democrat, renewed his call for Gonzales to step down. "Today's resignation by his chief of staff does not take the heat off the attorney general. It raises the temperature," he said.
But Gonzales responded by saying he was committed "to doing my job. And that is what I intend to do here on behalf of the American people."
Schumer said in a Senate speech that Gonzales offered "a sorry excuse" when he said, "I was not involved in seeing any memos, was not involved in any discussions about what was going on."
Sen. John Cornyn, a Texas Republican and one of Bush's most loyal supporters on Capitol Hill, expressed concern. "The appearances are troubling. ... This had not been handled well."
(Additional reporting by Tom Ferraro, Matt Spetalnick and Andy Sullivan)