Americans concerned that the war on terror has not yet sufficiently expanded the federal government's authority should breathe a little easier now that the Justice Department has released its new guidelines for the FBI. Everyone else might want to consider the expansion through the lens of the recent financial crisis.

The new rules grant the bureau broader investigatory powers. Among other things, they will permit agents to conduct inquiries in the absence of any evidence of wrongdoing. For instance, the bureau could investigate the likelihood of violence stemming from upcoming political demonstrations.

On one level, those changes represent a sensible way to make the bureau "a more flexible and adept collector of intelligence," as a post-9/11 commission recommended. They might help the bureau "connect the dots" before a terrorist attack, not afterward. This is greatly to be desired.

ON ANOTHER level, the changes raise legitimate concern that in the wrong hands the tools could be used to intimidate or harass Americans with unpopular agendas -- from Operation Rescue to ACORN, depending on who's running the show. (Earlier this year the public learned that in 2005 and 2006 Maryland State Police had infiltrated and spied on groups espousing anti-war and anti-capital-punishment views -- not exactly the stuff of seditious anarchy.)

It's worth noting that the bureau just recently finished wiping egg off its face. Director Robert Mueller had to apologize to The Washington Post and The New York Times for agents' attempts to obtain the phone records of Jakarta-based reporters, in contravention of FBI rules. This happened after the bureau paid $2 million to Brandon Mayfield, a Portland attorney who was detained for two weeks as a material witness in connection with the Madrid train bombings. No charges were ever brought. And the bureau already has greatly expanded its use of "National Security Letters" -- court-free warrant-like requests for information. From 2003 to 2005 the Bureau made more than 143,000 requests for information about more than 52,000 people.

It's also worth recalling the political pressure that can be brought to bear on agencies tasked with protecting the nation against its enemies. Recall the John Grisham-like tale Jim Comey told to Congress in testimony last year.

Comey, a former assistant U.S. attorney here in Richmond -- and one of the straightest arrows you could ever hope to meet -- served as deputy attorney general under John Ashcroft. While Ashcroft was incapacitated at George Washington Hospital in 2004, Comey refused to recertify the legality of the National Security Agency's infamous wiretapping program. White House Chief of Staff Andrew Card and White House legal counsel Alberto Gonzales tried to make an end-run around Comey, going to Ashcroft's hospital bed in the hopes of getting the groggy attorney general to sign off on the program. Comey beat them to Ashcroft's bedside by mere minutes and prevented them from getting what they wanted. A few months later Comey left the Justice Department for a job at Lockheed.

The story carries two salient lessons: (1) The nation's law-enforcement agencies are by and large led by stalwart defenders of law and liberty, and (2) they sometimes confront powerful forces who aren't. Giving the former the tools they need to do their job well without emboldening the latter is a delicate balancing act.

SOME WILL contend that the FBI should have whatever powers it needs to defeat America's terrorist enemies. But that begs the question. Absent evidence of wrongdoing, no one can say who is friend and who is foe (see: "Mayfield, Brandon"; "El-Masri, Khaled"; "Arar, Maher"; et al.). Finding out is the purpose of investigation, of course, and one wants to assume the bureau is not so overstaffed that it is likely to waste time looking up the bank records of community organizers who pose no real threat (see: "State Police, Md."). But then one wants to assume the bureau would not go digging around in the telephone records of newspaper reporters, too.

Of course the new rules for the FBI have been put in place with the best of intentions. That is nearly always the case. Rules put in place to require broader mortgage lending were put in place with the best of intentions, too. Some might even have said those rules, like the FBI's newly expanded powers, were entirely necessary. Yet necessity, as William Pitt said, is "the plea for every infringement of human freedom." And in the financial sector the consequences of those rules lately have helped drag the country into a deep fiscal morass.

Americans who admire the virtues of limited government should remember that what advocates of a change in law or regulation say it will do, or want it to do, ultimately is less important than what the change will do -- or permit to be done. The consequences cannot always be foreseen -- and sometimes the most serious consequences are the least intended.

My thoughts do not aim for your assent -- just place them alongside your own reflections for a while.

--Robert Nozick.
Contact A. Barton Hinkle at (804) 649-6627 or bhinkle@timesdispatch.com.