The chairman of the Senate Judiciary Committee said Sunday he expects a former Bush aide to testify before Congress this week about the firings of federal prosecutors despite White House objections.

Sen. Patrick Leahy's committee has subpoenaed Sara Taylor, a former White House political director, as part of its investigation into whether the Bush administration improperly ordered the U.S. attorneys dismissed. A hearing is scheduled for Wednesday.

Taylor's lawyer said she is willing to talk but does not want to defy President Bush, who has rejected subpoenas for documents from Taylor and for her testimony. Lawyer W. Neil Eggleston said Taylor expects a letter from White House lawyer Fred Fielding directing her not to comply on the basis of executive privilege.

"In our view, it is unfair to Ms. Taylor that this constitutional struggle might be played out with her as the object of an unseemly tug of war," Eggleston wrote House and Senate Judiciary committee leaders and Fielding over the weekend.

He added, "Absent the direction from the White House, Ms. Taylor would testify without hesitation before the Senate Judiciary Committee. She has committed no wrongdoing."

Leahy noted that lawmakers recently learned Taylor was among several White House aides who used an e-mail account at the Republican National Committee for political communications. Leahy said some e-mails relate to the investigation into the fired prosecutors. "There's certainly no executive privilege with something like that," Leahy said.

"We'll ask Miss Taylor when she does come before the committee this week just where she feels on this. I haven't heard anything from Mr. Fielding or anybody else at the White House that would justify a claim of executive privilege," Leahy said.

President Bush last month asserted executive privilege in rejecting subpoenas for documents from Taylor and his former counsel, Harriet Miers. Fielding argued that complying with such a request would damage the confidential nature of advice given the president. The White House also made clear — citing the same rationale — that Taylor and Miers would not testify before Congress as directed by the subpoenas.

White House spokesman Tony Fratto reiterated that stand on Sunday, despite Leahy's belief that Taylor would testify before his committee.

Bush has offered to make Miers, Taylor, political strategist Karl Rove and their aides available to be interviewed in private by the House and Senate committees, without transcripts and not under oath. Leahy and Democratic Rep. John Conyers of Michigan, the House committee chairman, have said the offer is insufficient.

Fratto urged them to reconsider and accused them of seeking confrontation and headlines. "The president remains ready and willing to share facts with the committees, but not under the threat of subpoenas and a media spectacle," he said.

The Senate committee's top Republican, Sen. Arlen Specter of Pennsylvania, recommended accepting the White House offer as a first step and issuing subpoenas later if needed. That led to an unusually candid exchange on live television in which Specter and Leahy negotiated how far they would bend in dealing with the Bush administration.

"One thing we haven't done is asked for a meeting with the president," Specter told Leahy. "Why don't you and John Conyers and I ask for a meeting with the president? We may be a little tired of dealing with his lawyer."

"Why don't you and I chat about this tomorrow when we're on the (Senate) floor," Leahy responded.

Lawmakers have given the White House until Monday morning to explain why the White House claimed executive privilege on subpoenaed documents related to the congressional investigation. Lawmakers also want an accounting of documents being withheld.

"I think it's time for the stonewalling to stop," Leahy said.

As Monday's deadline neared, Fratto said the White House will respond "in a manner consistent with the principle of the separation of powers." He declined to be more specific.

The Washington Post, citing unidentified sources, reported Sunday that Fielding was expected to tell lawmakers that he already has provided the legal basis for the executive privilege claims and does not intend to hand over the documentation sought.

Sen. Orrin Hatch, a senior Republican on Leahy's committee, defended the White House.

"There comes a point where the White House has to say, 'Hey, look there are certain confidential things in the White House that we're not going to share with Congress just like there are certain confidential things in Congress that we're not going to share with the White House,"' said Hatch, R-Utah.

The fight involves the investigation by Democratic lawmakers into the firings of several U.S. attorneys. The lawmakers want to know whether the White House improperly ordered the dismissals.

The investigation has expanded to include scrutiny of the administration's warrantless wiretapping program and Attorney General Alberto Gonzales' stewardship of the Justice Department.

Without an agreement on the subpoenaed documents, the dispute appears to be heading toward contempt citations and, possibly, a constitutional showdown in federal court.

Asked in a broadcast interview if the defiance would mean holding the White House in contempt of Congress, Conyers said, "Well, yes. It means moving forward in the process that would require him to comply with the subpoenas like most other people."

Conyers said he would not hold Taylor in contempt and he hoped negotiations with the White House might break the impasse.

"We keep getting stalled. They keep pressing us. We're seeking cooperation. This is not partisan in any way whatsoever. I would have the same attitude if it were a Democratic president," he said.

Conyers appeared on "This Week" on ABC, Hatch was on "Face the Nation" on CBS and Leahy and Specter spoke on "Late Edition" on a cable news channel.