Washington (CNN) Thirteen years ago this week, President George W. Bush was grappling with his administration's mishandling of Hurricane Katrina on the Gulf Coast when he suddenly had an opportunity to appoint the next chief justice of the United States. At his side was staff secretary Brett Kavanaugh.

Kavanaugh, now President Donald Trump's nominee to the Supreme Court, has said he remains struck by the "enormity of it all," a hectic set of days that represent, with the destruction in New Orleans and more than 1,000 related deaths, one of the darkest marks on Bush's domestic efforts. Those days also led to the choice of John Roberts to succeed William Rehnquist, who died on September 3, 2005.

In a 2015 speech, Kavanaugh asserted that his nearly six years with Bush, "especially my three years as staff secretary, were among the most interesting and most formative" in his development to be a judge. Kavanaugh in the same March 2015 speech at Marquette University referred to that early September week as "one of the worst weeks of the Bush presidency."

Yet presidential records of Kavanaugh's crucial time as Bush's staff secretary are not available to senators who will begin confirmation hearings Tuesday. Even the records that have been released, from Kavanaugh's three earlier years as a White House associate counsel, are substantively meager.

A CNN review of the documents found that many are items from the mass circulation of schedules, "talking points" and announcements and news clippings. The personal emails are frequently trivial or cryptic. Some are also redacted or missing the full chain of responses. Of about 270,000 pages released so far, a CNN analysis shows, only about 3% contain emails that appear to be written by Kavanaugh himself.

As a whole, the documents that have been released add little to the portrait of an individual poised for a lifetime appointment on the nation's highest court.

Senate Judiciary Chairman Chuck Grassley, R-Iowa, who has limited the records requested for release from the National Archives, has argued the focus should be on Kavanaugh's 12 years as a judge on the US Court of Appeals for the District of Columbia Circuit. The staff secretary job, Grassley said earlier this month, was "a non-legal position and wouldn't reveal anything about Judge Kavanaugh's legal thinking."

The committee's top Democrat, Sen. Dianne Feinstein, has countered that the staff secretary documents "are critical to understanding his knowledge of and involvement with torture, warrantless wiretapping and the use of signing statements, to name just a few key issues." The National Archives, which holds the presidential records, has said it is following its longstanding practice of responding only to document requests from the committee chairman, irrespective of which party is in power.

The controversy might, perhaps, be viewed as a sideshow in the politically polarized confirmation process. Yet the result is a major gap in the public understanding of a lawyer who held one of the most important jobs at the White House at one of the most important times for the country.

A president's staff secretary, overseeing the flow of information to the executive, can serve as one of his most trusted policy advisers and while not a well-known position, it has been held by well-known strategists, such as John Podesta, staff secretary to President Bill Clinton.

Throughout his time in the Bush White House, Kavanaugh was involved in the robust screening of candidates for the nation's powerful US appeals courts. He has told audiences that when he and other lawyers began in early 2001, the attitude was "pedal to the metal." His tenure covered several controversial nominees, including some who were blocked by Senate Democrats, and two appointees who eventually made it to the Supreme Court, first named to the DC Circuit Roberts, and Neil Gorsuch, whom Bush put on the Denver-based 10th Circuit and whom Trump named to the high court last year.

Yet the records released from his White House counsel days fail to illuminate Kavanaugh's work in this area. There is no window into his views of competing candidates for prominent vacancies or his strategic thinking when certain Bush choices were impeded by Senate Democrats.

The current White House counsel Don McGahn has demonstrated how much that office can assist in carrying out the president's broader agenda with the selection of leading conservative thinkers for the bench. McGahn steered Trump's selection of Kavanaugh to succeed retiring Justice Anthony Kennedy.

Amid domestic controversies over Katrina and judicial appointments during Kavanaugh's tenure, Bush also wrestled with post-September 11 anti-terrorism policy. Kavanaugh's role in Bush's policies involving the detention of terror suspects and their torture is certain to be raised in the Senate hearings. Some Democratic senators already have accused him of misrepresenting his involvement in such matters when he appeared before the Senate Judiciary Committee in 2006, for his current seat on the DC Circuit.

White House spokesman Raj Shah said Kavanaugh testified "accurately," adding, "He was not involved in crafting legal policies that formed the rules governing detention of combatants."

Fights over documents are perennial

Documents from a nominee's work behind the scenes in government can be more revealing of his or her thinking than published statements and the carefully choreographed public testimony of Senate hearings.

Kavanaugh has observed in public speeches that his work in the Bush administration involved disputes over executive branch records. One such clash occurred during the 2005 Bush nomination of Roberts, first to succeed retiring Associate Justice Sandra Day O'Connor and then to be chief justice following Rehnquist's death.

Bush's nomination of Roberts to be an associate justice was pending when Rehnquist died in the middle of the Katrina tragedy. Bush decided to elevate Roberts to the chief position. Then, for the O'Connor vacancy, Bush first chose White House Counsel Harriet Miers. When fellow conservatives protested that she lacked credentials, Bush turned to Samuel Alito, confirmed in January 2006.

No documents related to Kavanaugh's work on those nominations have been made public.

In the 2005 Roberts' records flap, the White House ensured production of the nominee's records from his years in the Reagan administration, where Roberts first served as a special assistant to the attorney general and then in the White House counsel's office.

Democratic senators had also wanted documents from Roberts' time as a deputy solicitor general in the George H.W. Bush administration. Those were held back as the Bush administration characterized his work in the US Solicitor General's office, which represents the government before the Supreme Court, as similar to work for a client. Such documents were also withheld by the Barack Obama administration when former solicitor general Elena Kagan was nominated for the Supreme Court in 2010. (She also had served in the Clinton White House, and those materials were made public during her confirmation hearing.)

The vast Reagan documents revealed some of Roberts' thinking on racial issues, women's rights, abortion, and religious liberty. All became grist for Senate questioning. Even with some controversy over his conservative stands in memos, Roberts was confirmed 78-22.

President Bush credits Kavanaugh with helping choose Roberts when Bush was torn, first, on a successor to O'Connor.

Bush was focused on Appeals Court Judges Roberts, then on the DC Circuit, Alito, on the Philadelphia-based Third Circuit, and Michael Luttig, then on the Richmond-based Fourth Circuit. "Brett told me that Luttig, Alito, and Roberts would all be solid justices," Bush recounted in his memoir, "Decision Points." "The tiebreaker question, he suggested, was which man would be the most effective leader on the Court -- the most capable of convincing his colleagues through persuasion and strategic thinking." Bush said he believed that would be Roberts.

Two months later, when Rehnquist died abruptly, he quickly decided to switch the nomination of Roberts, who had received early positive reviews from individual senators but had not begun Senate confirmation hearings.

For his part, Kavanaugh recounted the frenzied hours after he was alerted to Rehnquist's death late on a Saturday night. "I was responsible for hustling into the White House right away, contacting the president, immediately getting out a presidential written statement, and working with the speech-writers to help prepare the president's remarks," he said in a speech last year.

"When all of us met with the President in the Oval Office on Sunday morning, it did not take long for the president to settle on nominating John Roberts for the Rehnquist vacancy," Kavanaugh said.

The next morning Bush announced Roberts' nomination.

Then, said Kavanaugh, "we all took off for another trip to New Orleans and the Gulf Coast. ... The enormity of it all -- Katrina, Rehnquist, Roberts -- still hits me when I think about it in retrospect."