Why are administration officials increasingly worried that Al Qaeda might soon attack the US? Part of the answer may lie halfway around the world, in the wild terrain of northwestern Pakistan.
Washington's intelligence and security agencies say they've watched with increasing frustration in recent months as Al Qaeda's central leadership has reestablished core functions in Pakistan's tribal areas.
Al Qaeda now seems well settled in a haven in this remote, lightly governed area, say US officials. It's begun to conduct more terrorist training. The flow of money and communications to and from Osama bin Laden's top lieutenants appears to have increased.
In short, say US officials, Al Qaeda again has a headquarters, one of the main elements necessary for it to direct operations on US soil.
"We actually see Al Qaeda central being resurgent in their role in planning operations ... We see that activity rising," said John Kringen, the Central Intelligence Agency's director for intelligence, at a House Armed Services Committee hearing last week.
In recent weeks a chorus of US officials have talked publicly about their concern that Al Qaeda is reemerging as a threat to the US. On July 15, National Security Adviser Stephen Hadley in a broadcast interview said that recently he had seen some terrorism developments that are a "source of concern." Secretary of State Condoleezza Rice and Homeland Security Secretary Michael Chertoff previously have issued similar warnings.
US intelligence agencies are scheduled to send Congress a new National Intelligence Estimate (NIE) of the terrorist threat this week. The administration may issue an unclassified summary of the NIE within days.
Some critics complain that the warnings are exaggerated.
John Mueller, an Ohio State University professor of security studies, has long argued that one reason there have been no terror attacks on US soil since Sept. 11, 2001, is that there are no effective terrorist cells here, and that the media, the administration, and security contractors all have a vested interest in exaggerating the threat.
Some Democratic lawmakers say the warnings prove what they've said all along, that the central front on the war on terror is along the border between Afghanistan and Pakistan, not in Iraq. The US should have pursued Osama bin Laden, not Saddam Hussein, they say.
Last week the Senate overwhelmingly approved an amendment to the fiscal 2008 defense authorization bill that would require quarterly classified reports on the administration's efforts to bring to justice Mr. bin Laden and his top commanders.
"We still don't have them, and these are the people who are plotting to attack us now," said one of the amendment's sponsors, Budget Committee chairman Sen. Kent Conrad (D) of North Dakota.
Other experts say that it is entirely credible that Al Qaeda's leadership has become more active. The war in Iraq has been an effective recruiting tool, bringing in new flows of cash and recruits. At the same time, the Pakistani government has been unwilling or unable to threaten Al Qaeda's new HQ in the treacherous mountains of North and South Waziristan, and other wild border areas.
"Any sensible policymaker is going to err on the side of warning the American public, rather than trying to shield them," says Willam Martel, a Tufts University security expert and author of the new book "Victory in War: Foundations of Modern Military Policy."
The bottom line of the new National Intelligence Estimate is unsurprising: the US faces a persistent and evolving terrorist threat, and Islamic terrorist groups, especially Al Qaeda, remain the main danger to the US homeland.
"The organization is resilient and continues to plot attacks against high-profile targets with the objective of inflicting mass casualties," said Thomas Fingar, deputy director of National Intelligence for Analysis, at last week's House hearing.
The group maintains active lines of communications with affiliate groups in the Middle East and Europe, said Mr. Fingar. It has been successful both in rebuilding its central capabilities, and in "franchising" its name to satellite groups that want to build themselves up via association.
The job of third-ranking Al Qaeda leader is a dangerous one. "We regularly get to the number three person," said Fingar.
Pakistan's central government has virtually no authority in the area where Al Qaeda appears to have regrouped. Instead, Pakistani President Pervez Musharraf has struck peace deals with tribal leaders, ceding to them security control. These deals have "not been helpful," said Fingar last week.
The US does have the military power to take unilateral action in the area, intelligence officials assured House Armed Services panel members last week.
It has chosen not to do so, however, because of the uproar that might result in the rest of Pakistan. President Musharraf faces a deeply entrenched Islamist opposition, US officials said. "There is some risk of turning a problem in Northwest Pakistan into the problem of all of Pakistan," said Fingar.