Now experts tell NBC there was a clear tradeoff as the United States let up on al-Qaida to pursue regime change in Iraq.

A former national security official in the Bush administration tells NBC News Senior Investigative Correspondent Lisa Myers the White House was warned that the buildup against Saddam might provide a respite for Osama bin Laden and his henchmen. “There were decisions made,” says Flynt Leverett, a former director at the National Security Council in the Bush White House, “to take key assets, human assets, technical assets, out of theater in Afghanistan in order to position them for the campaign to unseat Saddam.”

Leverett, a former senior CIA analyst, talks with the professorial precision of an academic. “We see today,” he says, “that al-Qaida has been able to reconstitute leadership cells in the Afghanistan-Pakistan border region and it would seem in Eastern Iran.”