The commission probing the military and intelligence issues surrounding the Sept. 11, 2001, attacks will soon decide whether thousands of classified counterterrorism documents from the Clinton White House were unduly held back by President Bush's aides.

The decision will come as Bush's national security adviser, Condoleezza Rice (search), prepares to testify next Thursday as to what Clinton officials told the incoming Bush White House about the Al Qaeda terrorist network linked to the attacks and what the new administration did with the information.

Commissioners will have about two-and-a-half hours to quiz Rice about charges by former White House counterterrorism chief Richard Clarke (search) that the Bush administration was slow to act against the Al Qaeda threat despite warnings from him in January 2001.

"We want to find out about transition, we want to find out about the policies, want to find out about any policy differences," said panel Chairman Thomas H. Kean (search). "We want to find out any recommendations she has.

Kean said Sunday morning that within the next few weeks, Bush and Vice President Dick Cheney will appear before the group in a private session. They will answer questions together, as requested by the White House. Bush adviser Karen Hughes (search) says the rare joint appearance is appropriate.

"Many times President Bush and Vice President Cheney were in the room together in much of the events, much of the briefings ... extraordinary event ... I think it is appropriate they would appear together and discuss events leading up to Sept. 11," Hughes said un a Sunday television interview.

The Bush administration granted the federal panel access to the documents in question Friday after Bruce Lindsey (search), who was legal adviser to former President Clinton, said officials didn't turn over all of Clinton's records to the panel.

The commission's lawyers will begin reviewing the material Monday and should know by Tuesday if more documents should be released, panel commission spokesman Al Felzenberg said Friday.

"Mr. Lindsey voiced a concern. We shared the concern. So they have come up with a way of assuring us that we have access to the materials we need," Felzenberg said. "We'll know quickly if there are materials we should have or if they are duplicates."

Until then, Felzenberg said, the commission is withholding judgment as to why some documents weren't released.

"There's a lot of paper flying around. Let's see if there's more to the charge than we know," he said.

White House spokesman Scott McClellan defended the Bush White House, saying the administration had released all relevant documents but would make sure the commission's requests were filled.

"If the commission wants to go back and verify that some documents are duplicative or nonresponsive to their requests, then we are more than happy to work with the commission so that they can do so," McClellan said.

Meanwhile, Kean said Sunday that some of its findings will surprise the public when they're released this summer.

Kean also said he expects the commission's final report to be published before the November elections, possibly as early as July, even though the White House must clear it for intelligence problems.

The commission's deadline for submitting its report is July 26, extended from May 27 after complaints that the White House was delaying the turnover of necessary materials.

Kean, a former Republican governor of New Jersey, said he expects no similar foot-dragging as the White House vets the report for security lapses.

"Nobody has any interest in having the report sitting around Washington during the election period and pieces of it leaking out. Nobody has any interest in this thing coming out September or October, in the middle of the election," Kean said.

"So I think it is in the White House's interest, our interest, everybody's interest to get this out in July. And I believe they will."

When it is published, he said, both its findings and its recommendations for preventive action will draw attention.

"I've been surprised by some of what we've found, and so, I think, (the public) will, yes," Kean said on NBC's "Meet the Press."

On the counterterrorism issue, Lindsey charged Thursday that the commission wasn't getting a full picture of Clinton's anti-terrorism policies because the Bush administration had forwarded only 25 percent of the 11,000 records the former president wanted to provide the panel.

While such records are sealed by law for five years after a president leaves office, an exception was made to allow early access for the Sept. 11 panel. But the National Security Council (search) and Bush administration attorneys released only a fraction, Lindsey said.

Clinton and former Vice President Al Gore are scheduled to meet privately with the 10-member commission in the coming weeks to discuss whether anything could have been done to prevent the attacks.

A CBS News poll taken this week said seven in 10 Americans believe the Bush administration is either hiding something or lying about what it knew before the Sept. 11 attacks about possible terrorist attacks against the United States.

The Associated Press contributed to this report.