Accounts of a major restructuring of the FBI [news story, Nov. 11] to beef up its fight against terrorism and espionage did not mention that accompanying this effort would be a firm FBI commitment to the rules of the "Levi guidelines," which require that no investigation can take place without credible evidence of criminal conduct.

The Levi guidelines were promulgated by then-U.S. Attorney General Edward Levi during the Ford administration, after misbehavior and even criminal conduct by the FBI and the CIA documented by both the Senate and the House. Congressional reports found that the FBI in thousands of instances commenced investigations of individuals and organizations and continued them for years -- often for political purposes -- although no criminal conduct had been involved. The results were enormous damage to innocent people and a waste of FBI efforts and resources.

Although the Levi guidelines were somewhat weakened by Attorney General William French Smith in the Reagan administration, and although efforts in the '80s to codify them failed, the essential principle of the guidelines has continued to be respected by FBI directors.

While the FBI should be supported in its efforts to protect Americans, and while classified rules give it wider latitude in these investigations than in others, we must be vigilant in guarding against a return to the bad old days when foreign-sounding names or rhetoric critical of our government triggered an FBI investigation with damaging consequences to many thousands of Americans.

DON EDWARDS

Edgewater, Md.

The writer is a former Democratic representative from California.