WASHINGTON, April 18 — When Attorney General Alberto R. Gonzales takes the witness chair on Thursday before the Senate Judiciary Committee, the dismissal of the United States attorney from New Mexico will be a topic of particular scrutiny, committee members and their staff said.
That case, perhaps more than any of the other ousters, demonstrates the interaction of the Republican Party, the White House, a prominent Republican senator and Mr. Gonzales that led up to the firings.
Investigators have already determined that Mr. Gonzales spoke directly three times with Senator Pete V. Domenici, Republican of New Mexico, about his complaints regarding David C. Iglesias, the state’s former top federal prosecutor.
Administration officials have confirmed that Mr. Gonzales also spoke with President Bush and Karl Rove, the president’s chief political adviser, about the perceived lack of enthusiasm in Mr. Iglesias’s office, among others, for prosecuting voting fraud cases, a top Republican Party priority. And investigators know that Mr. Iglesias’s name was among the last to be added to the ouster list.
“On what precise date, why and by whom was Mr. Iglesias placed on the list of U.S. attorneys to be fired?” asked Senator Charles E. Schumer, Democrat of New York, in a list of questions he has presented to Mr. Gonzales.
Judiciary Committee staff members said Wednesday that given the repeated instances in which Mr. Gonzales was directly involved in discussions related to Mr. Iglesias, it might be hard for the attorney general to refuse to testify about these discussions or any follow-up conversations or to deny any recollection of them.
The attorney general’s appearance is regarded by lawmakers in both parties, by White House officials and by his own aides as the most important of his public life, with his job as the country’s chief legal officer hanging in the balance.
“His credibility is going to be an issue which is very much front and center,” Senator Arlen Specter, Republican of Pennsylvania, said Wednesday.
By ERIC LIPTON