Well, surprise. It turns out that the gumshoe patriots in the FBI have been at it again. Nice folks refer to it as "domestic surveillance," but it is nothing more or less than government-sanctioned spying on citizens who are politically active in ways that the political powers deem threatening. This time, the targets are people who are offended by the administration's support of the contras.

Last time, the targets were people who protested the war in Vietnam. Before that, the targets were people who did not support our policies toward Cuba, and before that the leaders of the civil rights movement were getting their phones bugged, mail opened and private as well as public conversations recorded for posterity. The FBI, like all secret police agencies, has a long and ugly history of repeated assaults on the civil rights of citizens who dare to dissent against ruling political interests. They are, after all, infinitely easier targets to deal with than, say, the runners for the Colombian cocaine cartel.

The lesson of this week's revelations that the FBI spied on more than a hundred groups that oppose this nation's policies in Central America is not so much that the spirit of J. Edgar Hoover lives, as some have put it. It goes far deeper than the extended influence of a single man.

The real lesson is that no one should be surprised: the secret police forces of governments throughout history have created whatever rules they deemed necessary to preserve the political establishment, and most particularly themselves. There is an internal dynamic within these agencies that puts them beyond the reach of those who govern as well as those who are governed. It doesn't seem to matter what the political structure of the country is: agencies given the power to police the population covertly do the dirty work of whatever government has unleashed them. The excuse is always the same: the political dissenter is engaged in "alleged criminal activity" and the secret police has got to find out what he's up to in order to protect the state.

The New York Times quotes an unnamed government official as saying the FBI started investigating the Committee in Solidarity with the People of El Salvador -- CISPES -- in 1981, after allegations were made (never proven) that the group had provided military assistance to leftist guerrillas in El Salvador. Note that Americans who've been helping the contras don't seem to have gotten nearly as much of the FBI's attention.

From then on, the FBI branched out to "investigate" a whole range of groups, ranging from its old nemesis, the Southern Christian Leadership Conference, to Catholic nuns and union locals, to the Women's Rape Crisis Center in Norfolk. In all, 52 of the 59 FBI field offices in the country were involved in various forms of surveillance such as attending college campus meetings and peace rallies to photographing protesters and writing down auto license numbers.

No one will ever be able to pin down how many hours, how much money, how many agents were involved -- or how many innocent people were harmed -- by unleashing yet another one of these secret government sweeps against political dissenters -- real or imaginary. Heaven alone knows what the Women's Rape Crisis Center in Norfolk could have been doing to get the attention of the FBI.

The FBI, we learned, was a rogue agency under Hoover. Under William Webster, Mr. Clean, it got a whole new set of guidelines designed to curb its intrusions into domestic politics. But old habits are hard to break.

We are all too familiar with the abuses of secret police forces in totalitarian regimes. The Iranian Savak did more to put the Ayatollah Ruhollah Khomeini in power than any other single instrument. But popularly elected governments that create these agencies inevitably create their own monsters.

Witness the current excesses of the Shin Bet against the Palestinians, and the excesses of the British domestic counter-intelligence agency, MI5, which have come to light in "Spycatcher." Former agent Peter Wright details how the agency "bugged and burgled" its way through foreign embassies in the 1950s and then sought to discredit its own Labor government in the '60s and '70s. More recently, the French government was internationally mortified when it was forced to admit that agents of its secret police sank Greenpeace's nuclear protest ship in New Zealand's territorial waters.

It is never clear who orders these things. Secret police agencies operate as a law unto themselves, and in return, they give their governments deniability. When that kind of deal exists, no one should be surprised at what happens.