No one at the Justice Department was lying, Holder said. He said department officials based their conclusion in the letter on the best information they had at the time from the Phoenix offices of ATF and the U.S. attorney.
Operation Fast and Furious was "a regional operation" and not "top to bottom," said Holder. The controversial tactic at issue in the operation was not a decision made in Washington, Holder said.
In explaining why the letter contained inaccuracies, Holder said "we were rushed" in responding to Grassley's inquiries. He said it would have been better to take two weeks to respond rather than the four or five days department lawyers set as their deadline.
Grassley, whose inquiry brought the tactic used in Operation Fast and Furious to light, is calling for Breuer's resignation.
Breuer has said he made a mistake in not telling Holder and the deputy attorney general that the controversial gun-walking tactic had been used in an earlier ATF probe called Operation Wide Receiver, which Breuer had known about since April 2010.
Grassley said that in addition to not informing his superiors, Breuer gave misleading answers when the senator asked whether Breuer had reviewed a draft of the inaccurate Justice Department letter to Congress last February.
Breuer told Congress he cannot say for sure whether he saw a draft of the inaccurate letter and that he has no recollection of having done so. At the time the letter was drafted, Breuer told one of the letter's main drafters in an e-mail, "As usual, great work."
Michael Chertoff, who early in the George W. Bush administration had the job Breuer now holds, spoke out on behalf of Breuer, whom Chertoff has known for over a dozen years.
"He's a very able, dedicated prosecutor," said Chertoff. "He acknowledged he was mistaken in not bringing this issue up to the attorney general at an earlier point in time and that's an admirable thing to do. I understand Sen. Grassley's feelings in this and I respect his feelings, but it would be a loss if Lanny were to leave."