This year's celebration of Martin Luther King's birthday should be an occasion to reflect on the unlearning of history's lessons. Today, as in the 1960s, federal agencies flout the Constitution in the name of a war against a foreign threat.

Thirty years ago a Senate select committee on intelligence activities, headed by Frank Church of Idaho, issued a report on abuses that included an 80-page chapter on the FBI's six-year counterintelligence program, or COINTELPRO. It was designed not merely to spy on King, but to neutralize and destroy him. Today more than ever, remembering the vendetta that FBI director J. Edgar Hoover was allowed to pursue against King seems as important as commemorating King's nonviolent quest for civil rights and social justice.

The FBI wiretapped King's home and his offices at the Southern Christian Leadership Conference as well as the phones of his colleagues. Agents installed microphones in hotel rooms to obtain information about the ''private activities of King and his advisers," information that could be used, in the words of an FBI memo, to ''completely discredit" them. These taped conversations were then used not as evidence in a legal procedure but in efforts to ruin King's reputation, to force him to stop trying to make America live up to its professed ideals, and even to try to push him to commit suicide.

Hoover's pretext for this scheme was an investigation of alleged communist infiltration. Two of King's advisers were suspected of being members of the Communist Party or being controlled by the party. Although it was never proved that either of the two was acting as a communist infiltrator, this rationale persuaded Attorney General Robert Kennedy in 1962 to authorize the COINTELPRO that made it possible for Hoover to pursue his obsessive efforts to destroy King.

The Church committee pinpointed the contradiction between rationale and reality. ''Rather than trying to discredit the alleged communists it believed were attempting to influence Dr. King," the report found, ''the Bureau adopted the curious tactic of trying to discredit the supposed target of Communist Party interest -- Dr. King himself."

Today's FBI seems to be looking for terrorists in all the wrong places, conducting extensive surveillance of such disparate groups as the Vegan Community Project, the Catholic Worker movement, and People for the Ethical Treatment of Animals. Hoover would not see that King was striving to save America from its real enemies within. And Hoover's heirs are still burrowing away at Americans' liberties. They confuse the unruliness of free speech with real threats to national security much as Hoover confused the true patriotism of King with Soviet subversion.

© 2006 The Boston Globe