Two meetings punctuate the day of FBI Deputy Director Thomas Pickard and show how federal law enforcement has been transformed since Sept. 11.

A tall, lanky man with an easy smile and the smooth gloss of a CEO, Pickard begins each day with a 7 a.m. briefing at the FBI's Strategic Information Operations Center, the command post for the massive federal investigation into the terror attacks. As the session starts, Pickard is joined by a senior official of the CIA who serves as his deputy. If CIA help is required, the intelligence officer makes a note to check the agency's files.

Exactly nine hours later, at 4 p.m., Pickard convenes another briefing inside a large executive briefing room that looks like an amphitheater, with big video screens on the walls and plush dark green leather seats.

Technicians patch agents in charge of the 56 FBI field offices into one giant conference call, and the seats fill up with officials from more than a dozen federal police, intelligence and military agencies. Pickard opens the discussion but defers to Assistant Attorney General Michael Chertoff, chief of the criminal division at the Justice Department. The conversation bounces around the nation, with updates of an investigation that has tentacles in every region.

The two meetings illustrate what nine years of terrorist attacks have wrought in the United States. The 7 a.m. briefing shows that although the FBI and the CIA remain separate agencies that operate under different laws and use different methods, they now act as one, senior officials for both agencies say.

The 4 p.m. briefing demonstrates how the Justice Department has forged the major federal law enforcement agencies and 94 local U.S. attorney's offices into a combined force centrally controlled from Washington.

The FBI's operations center on the fifth floor of its headquarters in downtown Washington is the nexus of those efforts, a vast mosaic of federal expertise and legal authorities. The FBI operations center is a 21st-century communications and data-processing platform that serves as a microcosm of the unified police and intelligence system.

At computer terminals throughout the 40,000-square-foot facility, personnel from the CIA, the Defense Intelligence Agency and the National Security Agency work alongside agents of the FBI, the U.S. Customs Service, the Secret Service and the Bureau of Alcohol, Tobacco and Firearms.

The FBI operations center is the mirror image of the counterterrorism center at CIA headquarters in Langley. There, too, the CIA, NSA, DIA, FBI, Customs and others work side-by-side. Just as Pickard's deputy is a CIA man, the chief of the CIA center has an FBI executive as his No. 2.

"All the walls are down," said FBI Assistant Director Thomas B. Locke.

A 'Seamless' Integration The foundation of this unified force was laid when a 2,000-pound bomb exploded beneath the World Trade Center on Feb. 26, 1993. Overwhelmed, the FBI sought help. Within 24 hours, agents from the Secret Service, the CIA and other agencies joined the existing FBI-New York Police Joint Terrorism Task Force.

That task force got results: A New York police detective searching the crime scene found a truck axle that led to the first arrest. A Secret Service agent obtained a full confession from Ramzi Yousef, the plot's mastermind.

Lessons learned from subsequent bombings forced more innovation.

The goal, said former deputy attorney general Jamie Gorelick, was a "seamless" integration of FBI and CIA capabilities that was also legal. In 1975, a Senate investigation of illegal domestic spying had led to changes designed to segregate the two agencies' operations.

"What the American people want is the best possible protection that they can have," Gorelick said. "They also don't want anyone collecting information on them inconsistent with the Fourth Amendment."

From 1995 to 2000, a series of anti-terrorism measures and spending bills headed the government back toward a unified system, an effort that was slowed by laws and institutional structures that were originally designed to limit federal power.

One by one, obstacles were overcome by presidents operating in periods of crisis. Now, the Bush administration is embarked on the most extensive rollback of constraints on federal police and intelligence power.

The vehicle for this is anti-terrorism legislation advocated by Attorney General John D. Ashcroft, versions of which were approved last week in the House and Senate.

The most controversial proposals are those that will make it lawful for the CIA and the U.S. military to tap into the awesome investigative might of the federal grand jury, the most powerful weapon in law enforcement's arsenal. If signed into law, the measure would allow prosecutors to readily share grand jury information with the CIA. That is crucial, a senior FBI official said, because it would allow the CIA access to some of the best information on Osama bin Laden's al Qaeda terrorist network.

The U.S. attorney's office in Manhattan has used a series of grand jury investigations after the 1993 World Trade Center bombing to assemble one of the largest and most carefully vetted bodies of evidence against bin Laden.

In tearing down the wall between federal grand juries and intelligence agencies, the Ashcroft proposal would also be removing the supervisory control of a federal judge, who under the current structure is the only person who can allow grand jury information to be shared.

Duke University law professor Sara Sun Beale, a former Justice Department official who is an authority on federal criminal law and the grand jury, said a key question is whether routine sharing of grand jury evidence with the CIA will gradually convert the grand jury into an engine of political intelligence-gathering.

"The grand jury was created to investigate criminal wrongdoing," Beale said. "It was given extensive authority to clear the innocent and discover evidence against the guilty." Historically, she said, judicial supervision and secrecy rules were integral parts of an official proceeding that can compel secret testimony and incarcerate uncooperative witnesses. "Now that we know the information that comes out at the end of the pipeline could be shared with intelligence agencies, how will the grand jury be used?" she asked.

In a frantic and ultimately losing battle, the nation's leading civil liberties groups argued that Ashcroft's approach would erode Fourth Amendment rights against unreasonable search and seizure and Fifth Amendment rights against self-incrimination.

Oklahoma City Model The World Trade Center bombing started the move to consolidate federal law enforcement, but it took another blast to build the new system. After the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City, the Justice Department developed "the Oklahoma City model."

Within hours of the explosion, Attorney General Janet Reno dispatched senior Justice Department officials to Oklahoma City to oversee the investigation and ordered other attorneys to coordinate the investigation from the FBI command center.

Thrown together on the fly, the Oklahoma City model relied on the FBI's antiquated, 4,000-square-foot command center. In the aftermath, Reno and then-FBI Director Louis J. Freeh got $20 million from Congress for a 10-fold expansion of the FBI operations center.

Richly stocked with computers and high-speed data transmission lines, the new center allows fingertip control of investigations in a way unheard of a decade ago.

On Sept. 11, when the second fuel-laden jet plowed into the World Trade Center, a crowd was watching on a giant video screen at the center's telecommunication center. At the time, two teams of agents were already at work in the center tracking bin Laden and Islamic fundamentalists.

Within 15 minutes of the first jet's attack, new teams of agents were pouring into the center's 20 rooms. Ultimately, more than 500 lawyers, agents, intelligence officers and support personnel worked 12-hour shifts in the center.

Near the middle of the facility is a state-of-the-art communications center, comparable to those found at the State Department and the CIA. It is surrounded by an expanse of office suites, conference rooms and large work areas with clusters of computer-equipped desks.

The operations center gives off an ambiance that falls somewhere between a big-city newsroom and a large insurance office. The entrance has large glass doors that announce "The George H.W. Bush Strategic Information Operations Center." The lights are bright, and the spaces are airy but windowless. The floors are made of a special anti-static material. The floor plan allows hundreds of people to work closely together in a logical flow.

The center's defining features are its walls, wiring and dimensions. With those building blocks, designers used architecture and technology to erase the barriers that had traditionally inhibited information-sharing among police and intelligence agencies.

The facility allows different teams of agents with different security clearances to work under one roof. The center's 65 miles of telephone and fiber-optic cable offer three types of local area networks: the regular FBI network that can connect to the networks of outside agencies; a classified network that operates at the level of Top Secret; and an even more highly classified Special Compartmented Information network.

"We can plug and play as we see fit," said Ronald Wilcox, deputy director of the operations center.

A visiting team of money-laundering experts from U.S. Customs can start working immediately on computers linked to Treasury's own network of databases. Teams from the intelligence community can tap into a secure interface with the CIA or the NSA.

The layout of the operations center is intended to help manage the flow of information from FBI field offices, other agencies and foreign sources. Agents use a computer software program called Rapid Start that enables field agents as well as supervisors in the operations center to review and synchronize work on tens of thousands of leads and suspects. Every FBI report of an interview is uploaded into the system for all to review.

A secure FBI intranet posts a constantly updated chronology of the case: what's happening, where it's happening and what has been discovered. As they sort through an endless cascade of information, analysts, agents and supervisors in the center can check the chronology on large video displays. Out in the field, each of the 56 FBI special agents in charge can view the chronology on their computer. "It keeps everyone on the same page," Locke said.

More than anything, the operations center is about control: of information, of operations, of a typhoon of a federal investigation.

On the afternoon of Sept. 11, Ashcroft knew where to find that control. He left the Justice headquarters building, crossed Constitution Avenue and commandeered an office suite in the FBI's operations center. Thereafter, he used the center to centralize the investigation in Washington.

Ashcroft was joined by 35 prosecutors from the Justice Department terrorism section as well as local prosecutors from the U.S. attorney's office for the Eastern District of Virginia. Assistant U.S. Attorney David N. Kelley, chief of Manhattan U.S. Attorney Mary Jo White's terrorism unit, was summoned to Washington to work full time in the operations center.

"We are not operating as a series of little offices," said Chertoff, the assistant attorney general in charge of the criminal division. "We are a single, unified team. This is a case unlike any that has been faced in the history of the United States. It is a national case, and we are approaching it as a national group of prosecutors."

A generation ago, it would have been unthinkable for the Justice Department to exercise such control. When Attorney General Robert F. Kennedy decided to mount a national assault on the Mafia, he met stiff resistance from the FBI and local U.S. attorneys. Out of frustration, he borrowed Treasury Department investigators and created regional strike forces staffed by criminal division lawyers from Washington.

As recently as 10 years ago, logistics and technology still posed significant obstacles. So did the continuing autonomy of local U.S. attorneys, who are independent presidential appointees.

All of this is changing, Chertoff and others say.

They contend that the Sept. 11 investigation, with its far-flung venues in Europe and the Middle East, can be controlled only in Washington. Statistics demonstrate the dimensions of the case, the biggest in U.S. history: Since the attacks, the FBI and other agencies have detained 698 people and served more than 4,000 subpoenas.

Chertoff and his colleagues in Washington approve every detention and subpoena.

"We are one organization," he said.

FBI Deputy Director Thomas Pickard, with Attorney General John D. Ashcroft, makes an announcement.