The vast majority of the newly disclosed flights were commercial airline flights, not charters, often carrying just two or three Saudi passengers. They originated from more than 20 cities, including Chicago, Dallas, Denver, Detroit and Houston. One Saudi Arabian Airlines flight left Kennedy Airport on Sept. 13 with 46 Saudis. The next day, another Saudi Arabian Airlines flight left with 13 Saudis.

The panel has indicated that it has yet to find any evidence that the F.B.I. checked the manifests of departing flights against its terror watch list. The departures of additional Saudis raise more questions for the panel. Richard Clarke, the former counterterrorism czar, told The Hill newspaper recently that he took full responsibility for approving some flights. But we don’t know if other Bush administration officials participated in the decision.

The passengers should have been questioned about any links to Osama bin Laden, or his financing. We have long known that some faction of the Saudi elite has helped funnel money to Islamist terrorists —inadvertently at least. Prince Ahmed bin Salman, who has been accused of being an intermediary between Al Qaeda and the House of Saud, boarded one of the evacuation planes in Kentucky. Was he interrogated by the F.B.I. before he left?

If the commission dares to address these issues, it will undoubtedly be accused of politicizing one of the most important national security investigations in American history — in an election year, no less.

But if it does not, it risks something far worse — the betrayal of the thousands of people who lost their lives that day, not to mention millions of others who want the truth.

Craig Unger is the author of “House of Bush, House of Saud: The Secret Relationship Between the World’s Two Most Powerful Dynasties.”