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A domestic intelligence agency patterned after Britain's MI5 (search) could be a hard sell in the United States; the debate alone is turning traditional adversaries into allies.

The possibility of a spy agency that could look like something out of a James Bond movie may be considered by the panel probing military and intelligence actions prior to the Sept. 11, 2001, terror attacks. Homeland Security Director Tom Ridge traveled to the United Kingdom to visit MI5 headquarters last year.

"MI5, which is the British intelligence agency, is probably something we don't want in America," California Rep. Jane Harman, the ranking Democrat on the House Intelligence Committee, told Fox News on Tuesday. "What we do want is one coordinated, integrated intelligence community that knows what it knows."

MI5 collects intelligence through communication intercepts such as wiretaps, surveillance and informants. Law enforcement is left to the police, who make the arrests.

A recent report by the National Commission on Terrorist Attacks Upon the United States (search) was highly critical of intelligence-sharing between U.S. agencies — FBI, CIA, the Defense Intelligence Agency and the National Security Agency — despite some significant post-Sept. 11 improvements.

Michael O'Hanlon, senior fellow at the Brookings Institution, said turf wars in Washington prevent any one agency from having a very effective intelligence-gathering and analyzing capability, noting that even the Department of Homeland Security has a weak intelligence component partly because of territoriality.

"I think right now we have to ask which agency has proved itself good at domestic intelligence and unfortunately the answer is no agency," O'Hanlon said.

Still, civil liberties groups, law enforcement, and intelligence officials from both the Clinton and Bush administrations are up in arms over the idea.

"Americans, I don't think, like secret police," former FBI Director Louis Freeh testified before the commission last week. "And you would, in effect, be establishing a secret police."

"The worst thing you can do is create another agency … then we’ll be back talking about whether they can share here or there or what," said Clinton Attorney General Janet Reno.

FBI Director Robert Mueller said so much progress has been made in breaking down the walls between the CIA and FBI, that the two agencies are now "integrated at virtually every level of our operation" and will be more so when the FBI's counterterrorism division is housed in the same building as that of the CIA.

"Splitting the law enforcement and the intelligence functions would leave both agencies fighting the war on terrorism with one hand tied behind their backs," Mueller testified.

CIA Director George Tenet said intelligence and law enforcement must go hand-in-hand, but the Sept. 11 panel, in a staff report, noted that CIA efforts, in particular, were challenged by staffing limitations and the daily demands of issuing fresh intelligence summaries to policy-makers.

Tenet said he has "serious issues" with the report, which indicated that the CIA director does not have a strategic plan to handle the War on Terror or to collect and manage intelligence data.

"That's flat wrong," Tenet said, adding that the current process "ain't perfect … but we've made an enormous amount of progress.

"The implication that the intelligence community can't talk to each other is wrong," he said.

Among those who oppose a domestic spy agency are critics who point to abuses under former FBI Director J. Edgar Hoover (search), who targeted civil rights workers, anti-war activists and others whose politics were opposed to his. But those who support a new domestic intelligence branch believe those fears are outdated.

"We are not in the days of J. Edgar Hoover anymore," O'Hanlon said. "The United States has too many different people watching the behavior of government. I'm relatively confident we can prevent serious abuses.

"We have to recognize that we may have to draw that line between civil liberties and search for harmful terrorist at a slightly different place than we used to in the past."

But groups like the American Civil Liberties Union (search) oppose an MI5-style agency.

"Creating a domestic agency would be bad for civil liberties and bad for security," said Gregory Najeimi of the ACLU. "We haven't had a domestic CIA since the country was founded. We went through all the years of the Cold War without a domestic CIA, we don't need one now."

Najeimi said an agency like this would just add to the federal bureaucracy currently in Washington.

"It would be bad for security because instead of solving the stove-piping problem where agencies aren't sharing information, it would create a new one," he said. "It would add a new wall, not take one down."

Jim Dempsey, executive director of the Center for Democracy and Technology (search), said although many Americans want a tough response to terrorism, "they want it controlled and subject to control, oversight, checks and balances and they're afraid a spy agency would run afield without those kind of controls."

Dempsey and others pointed out that within the past several decades, MI5 has engaged in political spying, and on occasion has failed to hand off advance information it had about terrorist activities.

"I just think that an intelligence agency domestically, cut off from the criminal justice system and all the Bill of Rights that that entails, I think, is fraught with danger," Dempsey said.

Another option is to create a national director of intelligence who would oversee intelligence-gathering efforts. Some experts say that's just what the country needs.

"It's just too big a job for one person" Skip Brandon, former FBI deputy assistant director of counterintelligence, said of the current job of director of central intelligence. "This is a good idea."

Former National Security Adviser Brent Scowcroft (search) submitted the concept as part of a review of intelligence gathering after the Sept. 11 attacks. The idea has been on the table for more than a year.

Though President Bush said last week that he was open to new thoughts on the subject on centralizing intelligence gathering, sources told Fox News that no decision of this kind is imminent or is it currently being viewed as an alternative to the final recommendations from the Sept. 11 commission.

Fox News' Jim Angle, Major Garrett, Catherine Herridge and Liza Porteus contributed to this report.