As 2001 began, counterterrorism officials were receiving frequent but fragmentary reports about threats. Indeed, there appeared to be possible threats almost everywhere the United States had interests-including at home.

"THE SYSTEM WAS BLINKING RED"

To understand how the escalation in threat reporting was handled in the summer of 2001, it is useful to understand how threat information in general is collected and conveyed. Information is collected through several methods, including signals intelligence and interviews of human sources, and gathered into intelligence reports. Depending on the source and nature of the reporting, these reports may be highly classified-and therefore tightly held-or less sensitive and widely disseminated to state and local law enforcement agencies. Threat reporting must be disseminated, either through individual reports or through threat advisories. Such advisories, intended to alert their recipients, may address a specific threat or be a general warning.

Because the amount of reporting is so voluminous, only a select fraction can be chosen for briefing the president and senior officials. During 2001, Director of Central Intelligence George Tenet was briefed regularly regarding threats and other operational information relating to Usama Bin Ladin.¹ He in turn met daily with President Bush, who was briefed by the CIA through what is known as the President's Daily Brief (PDB). Each PDB consists of a series of six to eight relatively short articles or briefs covering a broad array of topics; CIA staff decides which subjects are the most important on any given day. There were more than 40 intelligence articles in the PDBs from January 20 to September 10, 2001, that related to Bin Ladin. The PDB is considered highly sensitive and is distributed to only a handful of high-level officials.²

The Senior Executive Intelligence Brief (SEIB), distributed to a broader group of officials, has a similar format and generally covers the same subjects as the PDB. It usually contains less information so as to protect sources and methods. Like their predecessors, the Attorney General, the FBI Director, and Richard Clarke, the National Security Council (NSC) counterterrorism coordinator, all received the SEIB, not the PDB.³ Clarke and his staff had extensive access to terrorism reporting, but they did not have access to internal, nondisseminated information at the National Security Agency (NSA), CIA, or FBI.