WASHINGTON (CNN) -- "A House committee is requesting Justice Department documents on a data-mining project that reportedly identified the senders and recipients of calls and e-mails intercepted via the National Security Agency's eavesdropping program.
In a Monday letter, Rep. John Conyers, chairman of the House Judiciary Committee, asked Attorney General Alberto Gonzales to hand over "all opinions, memoranda and background materials, as well as any dissenting views, materials and opinions" about the data-mining program.
On Tuesday, a group of congressmen announced they had introduced a resolution calling for an investigation to determine whether the attorney general should beimpeached.
While the Bush administration has acknowledged OK'ing the controversial program in which the government wiretapped phone calls without obtaining a warrant, it has remained mum on whether it authorized the NSA to use computers to sift through databases to identify who participated in intercepted communications. (The computers reportedly do not identify the contents of the communications.)
Critics have said the surveillance program violates a 1978 act requiring a special court's approval before eavesdropping on communications in intelligence cases.
In his letter, Conyers wrote that his committee is considering changes to the Foreign Intelligence Surveillance Act and therefore must be "fully apprised of these controversial, and possibly unlawful, programs."
The Michigan Democrat continued, "It is difficult to craft appropriate legislative responses unless we have all of the relevant facts concerning these programs."
The embattled Gonzales is at the center of the controversy and is presently defending himself against allegations that he lied to Congress about a dispute between the White House and Justice Department over the eavesdropping program's legality.
Gonzales has denied there was any significant dissent over the program in the Justice Department, but former Deputy Attorney General James Comey and FBI Director Robert Mueller have indicated otherwise.
At issue is a 2004 late-night hospital visit to then-Attorney General John Ashcroft, which Gonzales claims did not involve discussion of "the terrorist surveillance program that the president announced to the American people." Mueller testified last week that Ashcroft told him it did involve the program.
A former government official familiar with the program said over the weekend that the dispute was so contentious some officials, including Comey, threatened to resign from the administration in protest.
Last week, Gonzales told a Senate committee that the dispute involved "other intelligence activities," which he declined to discuss. The former government official said that the dispute centered on data mining, not eavesdropping.
Gonzales will lean heavily on this distinction as he defends himself against perjury charges.
Democrats, however, say it doesn't matter because the data-mining project was a facet of the NSA eavesdropping program. Also, the former government official who confirmed the existence of the data-mining program has said Gonzales "may have been splitting hairs."
In his letter to Gonzales, Conyers questioned whether the White House leaked classified information about the data-mining program "to rehabilitate previous controversial testimony by you." Conyers further said that the Judiciary Committee wants to know if the Justice Department knew about the leaks or authorized them.
National Intelligence Director Mike McConnell and other top administration officials briefed a group of lawmakers on the issue Monday. Gonzales' testimony was discussed during that session, said Sen. Arlen Specter, the ranking Republican on the Senate Judiciary Committee.
Specter added that the Bush administration has agreed to address the matter in writing by Tuesday, but the senator would not disclose what else was discussed during the 80-minute briefing, nor would he divulge which lawmakers attended.
The White House is "preparing" the letter requested by Specter, spokesman Tony Snow said Tuesday. He would not comment on a deadline or the letter's contents but said it would be delivered Tuesday.
President Bush acknowledged the NSA eavesdropping program in December 2005 and defended it as a vital counterterrorism tool. The program was authorized to intercept communications coming into or out of the United States involving people suspected of having links to al Qaeda, Bush said.
But the administration has not acknowledged using computers to identify who sent or received millions of Americans' phone calls and e-mails.
Gonzales' disputed statements -- coupled with an ongoing controversy over the allegedly political dismissals of eight U.S. attorneys last year -- have sparked bipartisan calls for the attorney general's resignation or ouster.
On Tuesday, Rep. Jay Inslee, D-Washington, said he introduced a resolution calling for the House Judiciary Committee to investigate whether Gonzales should be impeached "for high crimes and misdemeanors."
Inslee said Gonzales' alleged actions constitute "a national embarrassment." In addition to the issues involving the U.S. attorneys and the eavesdropping program, Inslee also said Gonzales had politicized the U.S. judicial system and been dishonest with Congress and the American people.
"He has placed his loyalty to one man above his loyalty to the U.S. Constitution and that cannot stand," Inslee said referring to Gonzales' longtime allegiance to Bush. "We have a very deep scar on the integrity of the judicial system now."
Previously, Republican Rep. Christopher Shays of Connecticut said Gonzales doesn't have much credibility "and he would do us all a favor if he stepped down and allowed the president to select someone else."
Last week, four Democratic senators called for the appointment of a special prosecutor to determine if Gonzales has committed perjury.
But the president has stood by his longtime ally, who has been alongside him since 1995, during Bush's days as Texas governor. Vice President Dick Cheney also has run to Gonzales' defense.
"I think Al has done a good job under difficult circumstances," Cheney told CBS Radio on Monday. "The debate between he and the Senate is something they're going to have to resolve, but I think he has testified truthfully."
Cheney said he disagreed with Specter, who called Sunday for Gonzales to step down.
"I think the key is whether or not [Gonzales] has the confidence of the president, and he clearly does," Cheney said.
On Tuesday, Cheney continued his defense of Gonzales, saying that he stood by him and held him "in high regard."
"With respect to the U.S. attorneys, there has been, I think, a bit of a witch hunt on Capitol Hill as they keep rolling over rocks hoping they can find something, but there really hasn't been anything that has come up to suggest that there was any wrongdoing on any kind," Cheney said."
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