According to William Hamilton, a former NSA intelligence officer who left the agency in the 1970s, that description sounded a lot like Main Core, which he first heard about in detail in 1992. Hamilton, who is the president of Inslaw Inc., a computer services firm with many clients in government and the private sector, says there are strong indications that the Bush administration's domestic surveillance operations use Main Core.

Hamilton's company Inslaw is widely respected in the law enforcement community for creating a program called the Prosecutors' Management Information System, or PROMIS. It keeps track of criminal investigations through a powerful search engine that can quickly access all stored data components of a case, from the name of the initial investigators to the telephone numbers of key suspects. PROMIS, also widely used in the insurance industry, can also sort through other databases fast, with results showing up almost instantly. "It operates just like Google," Hamilton told me in an interview in his Washington office in May.

Since the late 1980s, Inslaw has been involved in a legal dispute over its claim that Justice Department officials in the Reagan administration appropriated the PROMIS software. Hamilton claims that Reagan officials gave PROMIS to the NSA and the CIA, which then adapted the software -- and its outstanding ability to search other databases -- to manage intelligence operations and track financial transactions. Over the years, Hamilton has employed prominent lawyers to pursue the case, including Elliot Richardson, the former attorney general and secretary of defense who died in 1999, and C. Boyden Gray, the former White House counsel to President George H.W. Bush. The dispute has never been settled. But based on the long-running case, Hamilton says he believes U.S. intelligence uses PROMIS as the primary software for searching the Main Core database.

Hamilton was first told about the connection between PROMIS and Main Core in the spring of 1992 by a U.S. intelligence official, and again in 1995 by a former NSA official. In July 2001, Hamilton says, he discussed his case with retired Adm. Dan Murphy, a former military advisor to Elliot Richardson who later served under President George H.W. Bush as deputy director of the CIA. Murphy, who died shortly after his meeting with Hamilton, did not specifically mention Main Core. But he informed Hamilton that the NSA's use of PROMIS involved something "so seriously wrong that money alone cannot cure the problem," Hamilton told me. He added, "I believe in retrospect that Murphy was alluding to Main Core." Hamilton also provided copies of letters that Richardson and Gray sent to U.S. intelligence officials and the Justice Department on Inslaw's behalf alleging that the NSA and the CIA had appropriated PROMIS for intelligence use.
Hamilton says James B. Comey's congressional testimony in May 2007, in which he described a hospitalized John Ashcroft's dramatic standoff with senior Bush officials Alberto Gonzales and Andrew Card, was another illuminating moment. "It was then that we [at Inslaw] started hearing again about the Main Core derivative of PROMIS for spying on Americans," he told me.

Through a former senior Justice Department official with more than 25 years of government experience, Salon has learned of a high-level former national security official who reportedly has firsthand knowledge of the U.S. government's use of Main Core. The official worked as a senior intelligence analyst for a large domestic law enforcement agency inside the Bush White House. He would not agree to an interview. But according to the former Justice Department official, the former intelligence analyst told her that while stationed at the White House after the 9/11 attacks, one day he accidentally walked into a restricted room and came across a computer system that was logged on to what he recognized to be the Main Core database. When she mentioned the specific name of the top-secret system during their conversation, she recalled, "he turned white as a sheet."

An article in Radar magazine in May, citing three unnamed former government officials, reported that "8 million Americans are now listed in Main Core as potentially suspect" and, in the event of a national emergency, "could be subject to everything from heightened surveillance and tracking to direct questioning and even detention."

According to a senior government official who served with high-level security clearances in five administrations, "There exists a database of Americans, who, often for the slightest and most trivial reason, are considered unfriendly, and who, in a time of panic, might be incarcerated. The database can identify and locate perceived 'enemies of the state' almost instantaneously." He and other sources tell Radar that the database is sometimes referred to by the code name Main Core. One knowledgeable source claims that 8 million Americans are now listed in Main Core as potentially suspect. In the event of a national emergency, these people could be subject to everything from heightened surveillance and tracking to direct questioning and possibly even detention.

Of course, federal law is somewhat vague as to what might constitute a "national emergency." Executive orders issued over the past three decades define it as a "natural disaster, military attack, [or] technological or other emergency," while Department of Defense documents include eventualities like "riots, acts of violence, insurrections, unlawful obstructions or assemblages, [and] disorder prejudicial to public law and order." According to one news report, even "national opposition to U.S. military invasion abroad" could be a trigger.

Let's imagine a harrowing scenario: coordinated bombings in several American cities culminating in a major blast—say, a suitcase nuke—in New York City. Thousands of civilians are dead. Commerce is paralyzed. A state of emergency is declared by the president. Continuity of Governance plans that were developed during the Cold War and aggressively revised since 9/11 go into effect. Surviving government officials are shuttled to protected underground complexes carved into the hills of Maryland, Virginia, and Pennsylvania. Power shifts to a "parallel government" that consists of scores of secretly preselected officials. (As far back as the 1980s, Donald Rumsfeld, then CEO of a pharmaceutical company, and Dick Cheney, then a congressman from Wyoming, were slated to step into key positions during a declared emergency.) The executive branch is the sole and absolute seat of authority, with Congress and the judiciary relegated to advisory roles at best. The country becomes, within a matter of hours, a police state.

And -

Under law, during a national emergency, FEMA and its parent organization, the Department of Homeland Security, would be empowered to seize private and public property, all forms of transport, and all food supplies. The agency could dispatch military commanders to run state and local governments, and it could order the arrest of citizens without a warrant, holding them without trial for as long as the acting government deems necessary. From the comfortable perspective of peaceful times, such behavior by the government may seem far-fetched. But it was not so very long ago that FDR ordered 120,000 Japanese Americans—everyone from infants to the elderly—be held in detention camps for the duration of World War II. This is widely regarded as a shameful moment in U.S. history, a lesson learned. But a long trail of federal documents indicates that the possibility of large-scale detention has never quite been abandoned by federal authorities. Around the time of the 1968 race riots, for instance, a paper drawn up at the U.S. Army War College detailed plans for rounding up millions of "militants" and "American negroes," who were to be held at "assembly centers or relocation camps." In the late 1980s, the Austin American-Statesman and other publications reported the existence of 10 detention camp sites on military facilities nationwide, where hundreds of thousands of people could be held in the event of domestic political upheaval. More such facilities were commissioned in 2006, when Kellogg Brown & Root—then a subsidiary of Halliburton—was handed a $385 million contract to establish "temporary detention and processing capabilities" for the Department of Homeland Security. The contract is short on details, stating only that the facilities would be used for "an emergency influx of immigrants, or to support the rapid development of new programs." Just what those "new programs" might be is not specified.

In the days after our hypothetical terror attack, events might play out like this: With the population gripped by fear and anger, authorities undertake unprecedented actions in the name of public safety. Officials at the Department of Homeland Security begin actively scrutinizing people who—for a tremendously broad set of reasons—have been flagged in Main Core as potential domestic threats. Some of these individuals might receive a letter or a phone call, others a request to register with local authorities. Still others might hear a knock on the door and find police or armed soldiers outside. In some instances, the authorities might just ask a few questions. Other suspects might be arrested and escorted to federal holding facilities, where they could be detained without counsel until the state of emergency is no longer in effect.

Lt. Col. Oliver North also may have been using the program. According to several intelligence community sources, PROMIS was in use at a 6,100-square-foot command center built on the sixth floor of the Justice Department. According to both a contractor who helped design the center and information disclosed during the Iran-Contra hearings, Oliver North had a similar, but smaller, White House operations room that was connected by computer link to the DOJ's command center.

Using the computers in his command center, North tracked dissidents and potential troublemakers within the United States as part of a domestic emergency preparedness program, commissioned under Reagan's Federal Emergency Management Agency (FEMA), according to sources and published reports. Using PROMIS, sources point out, North could have drawn up lists of anyone ever arrested for a political protest, for example, or anyone who had ever refused to pay their taxes. Compared to PROMIS, Richard Nixon's enemies list or Sen. Joe McCarthy's blacklist look downright crude. This operation was so sensitive that when Rep. Jack Brooks asked North about it during the Iran-Contra hearings, the hearing was immediately suspended pending an executive (secret) conference. When the hearings were reconvened, the issue of North's FEMA dealings was dropped.