The firing of eight U.S. attorneys could have been handled better, but the prosecutors were not dismissed for any "improper reason," Attorney General Alberto Gonzales will say Tuesday.

According to remarks prepared for delivery to the Senate Judiciary Committee, one of several congressional panels probing last December's dismissals, Gonzales insists that he has "nothing to hide" from investigators.

"I have taken ... important steps to provide information for two critical reasons: (1) I have nothing to hide, and (2) I am committed to assuring the Congress and the American public that nothing improper occurred here," he said in the remarks released Sunday.

Gonzales concedes that the Justice Department's handling of the dismissals ended up creating an "unfortunate and undignified public spectacle," but at no time were any of the prosecutors' fates decided based on political considerations aimed at encouraging or killing partisan prosecutions.

"I know that I did not, and would not, ask for a resignation of any individual in order to interfere with or influence a particular prosecution for partisan political gain," Gonzales is expected to say. "I also have no basis to believe that anyone involved in this process sought the removal of a U.S. attorney for an improper reason."

"Our record in bringing aggressive prosecutions without fear or favor and irrespective of political affiliations — a record I am very proud of — is beyond reproach. While reasonable people may dispute whether or not the actual reasons for these decisions were sufficient to justify a particular resignation, again, there is no factual basis to support the allegation, as many have made, that these resignations were motivated by improper reasons," Gonzales' remarks continue.

The release of his statement followed the printing of an op-ed on Sunday in The Washington Post in which Gonzales apologized for the handling of the matter, including a series of misstatements about his exact role that he acknowledged has "created confusion."

Click here to read the op-ed in The Washington Post.

Gonzales' testimony on Tuesday could be a make-or-break moment for the attorney general, whose conflicting statements about his involvement have led to calls for his resignation by many Democrats and some Republicans.

Two of those senators said Sunday that he has an uphill battle in convincing senators he's capable of running the Justice Department.

"He's got a steep hill to climb," said Sen. Arlen Specter, R-Pa., the top Republican on the Senate Judiciary Committee. "He's going to be successful only if he deals with the facts."

Specter said none of Gonzales' public statements so far has convinced him that the department's ouster of eight U.S. attorneys was justified.

"Those statements are very conclusory," he said.

Sen. Lindsey Graham, R-S.C., another member of the Judiciary Committee, said Gonzales has "an uphill struggle to re-establish his credibility with the committee given prior statements." Still, Graham said he believed Gonzales could save his job.

"He needs to explain what he did and why he did it," Graham said. "There are three our four different versions of his role in this, and he needs to bring clarity to what he did and why he did it."

In his statement to Congress, Gonzales details the process by which the attorneys were fired. He explains that he and his aides decided not to fire all 93 U.S. attorneys after the 2004 election because he says it would've been too disruptive. Gonzales then says he left the review process on individual prosecutors up to his then-chief of staff Kyle Sampson and a small cadre of individuals, including Deputy Attorney General Paul McNulty, who were better aware of the prosecutors' performances.

Gonzales says from that point on he was not very involved in the process, having received few briefings and offering little guidance on who should or should not be removed. He says he only remembers two names being suggested to him as possible replacements — Assistant Attorney General Rachel Brand and prosecutor Deborah Rhodes

"I do not recall my response or any other discussion. Nor do I recall the timing of when this was raised with me," Gonzales will tell the committee. "Although these names were mentioned to me, I do not recall making any decision, either on or before Dec. 7, 2006, about who should replace the U.S. attorneys who were asked to resign that day."

He adds that he accepted the recommendations because they "represented the consensus of senior Justice Department officials most knowledgeable about the performance of all 93 U.S. attorneys" and he believed the process had been based on their performances alone.

"In hindsight, I would have handled this differently," Gonzales is to say. "Looking back, it is clear to me that I should have done more personally to ensure that the review process was more rigorous, and that each U.S. Attorney was informed of this decision in a more personal and respectful way."

Sampson left the Justice Department over the controversy on March 12. He told the Senate Judiciary Committee on March 29 that he remembered discussions with Gonzales "this process of asking certain U.S. attorneys to resign." Schumer said he was up on Capitol Hill on Sunday answering follow-up questions from committee staff.

Sen. Charles Schumer, D-N.Y., who leads the subcommittee that has been in charge of the investigation, said he found it odd that Gonzales would pin the firings process on Sampson.

"The only important theme that can be gleaned from the attorney general's opening statement is that he points the finger of responsibility at Kyle Sampson for determining who was fired and why," Schumer said in an afternoon press conference. "Kyle Sampson has denied he was the decision-maker. He claimed to be merely a record keeper. ... All I can say is that his opening statement doesn't move us one tittle forward in terms of finding out what happened."

In the 22-page testimony — of which five pages are dedicated to the attorney firings and the rest deals with Department of Justice initiatives — Gonzales mentions the eight attorneys by name just once, when he thanks them for their service and apologizes for dragging them through such a public vetting of their performances.

"The Justice Department owes them more respect than they were shown. In some cases, department leaders should have worked with them to make improvements where they were needed. In all cases, I should have communicated the concerns more effectively, and I should have informed them of my decisions in a more dignified manner. This process could have been handled much better and for that I want to apologize publicly," he says, while also offering suggestions for improving future evaluations.

Gonzales' testimony may not be enough for lawmakers, including Specter, who said Gonzales must explain the firings on a case by case basis, and must convince senators they were not done to interfere with or promote ongoing criminal investigations aimed at benefiting Republicans.

"The No. 1 question is, is he capable of administering the Department of Justice, did he have enough hands on to know what's happening?" Specter said. "Can he explain why these individuals were asked to resign and justify the reasons for doing so?"

While Gonzales is in for a tough time from senators on both sides of the aisle, he did win the support of Vice President Dick Cheney, who said Sunday that he and President Bush have "every confidence" in Gonzales and look forward to hearing his testimony. But, he said he has little knowledge of the conflict.

"This took place inside the Justice Department," Cheney said on "Face the Nation" on CBS. "The one who needs to answer to that and lay out on the record the specifics of what transpired is the attorney general, and he'll do so."

Specter spoke on ABC's "This Week," and Graham appeared on "FOX News Sunday."

FOX News' Sharon Kehnemui Liss and The Associated Press contributed to this report.