This week's conviction of former Ku Klux Klansman Thomas E. Blanton 38 years after he helped kill four little black girls in a Birmingham church is yet one more reason to wonder why J. Edgar Hoover's name is on the FBI building in Washington. Because of Hoover's 1965 decision to quash the FBI investigation of the 1963 Birmingham church bombing, justice may have been delayed in one of the Ku Klux Klan's worst acts of racial violence in the civil rights era.

There's reason to believe that Thomas Blanton might not have roamed the streets of Alabama as a free man for nearly 40 years had matters been left up to the FBI's Birmingham field office. Labeled a prime suspect by the bureau within weeks of the heinous crime, Blanton was questioned several times and polygraphed by bureau agents. His lie detector test revealed "evidence of deception" when he denied having anything to do with the bombing. And Blanton wasn't alone.

Two years after that Sunday morning travesty, FBI agents had lined up documents, wiretaps and witnesses against him and three other prime suspects: ex-Klansmen Robert E. Chambliss a k a "Dynamite Bob," Bobby Frank Cherry and Herman Frank Cash. It wasn't easy compiling the evidence. The Ku Klux Klan had loads of friends and supporters around the state, especially among cops and state troopers. The case against ex-Klansmen would have to be taken before a white jury in Birmingham -- a city also known at the time as "Bombingham" because of all the KKK dynamite used against the homes and churches of black leaders in the 1950s and '60s. But the agents believed they had compiled a case strong enough to overcome white bias.

However, J. Edgar Hoover, ensconced in his fiefdom and believing himself answerable to no one, killed the inquiry. Agents asked to send information fingering Blanton and his fellow Klansmen to the Justice Department's civil rights division lawyers for a legal opinion. The authoritarian Hoover blocked that request. An FBI agent who found witnesses placing the suspects at the bombing scene sought permission to brief the local U.S. attorney and state prosecutor. Hoover turned that down, too. Not that J. Edgar Hoover had any business deciding what made a prosecutable case -- that was supposed to be a Justice Department call. But Washington was Hoover's world. So the FBI director simply declared the chances for success "very remote" and ordered the documents sealed and withheld from prosecutors.

It took Hoover's death, the persistence of the victims' families, a tenacious Alabama detective years later, work by a new group of Birmingham field office FBI agents using the 1960s files and a determined U.S. attorney in Birmingham to bring about a courtroom victory that many of us feared would never come. No thanks to J. Edgar Hoover, Blanton is finally going to pay for that Sunday morning bombing at the Sixteenth Street Baptist Church.

Blanton's four life sentences have taken him off the streets for good. With now deceased fellow Klansman "Dynamite Bob" Chambliss convicted of murder in the bombing case on state charges in 1977 (reportedly based on less evidence than Hoover refused to provide prosecutors 13 years earlier), and the death of Herman Cash in 1994 -- who departed this world a free man -- only one of Blanton's alleged accomplices is left to face the bar of justice: Bobby Frank Cherry, who was indicted with Blanton last year.

But that's not the only unfinished Birmingham bombing business. The name of the man responsible for blocking prosecution in the most inhumane act of racial violence in the '60s is emblazoned at the entrance of the FBI building. That is a disgrace. It ought to be removed.

But it won't be.

Calls to take a hammer and chisel to Hoover's name have been heard before. And ignored. Hoover's relentless persecution of Dr. Martin Luther King Jr. should have been reason enough. It wasn't. That Hoover was a mean-spirited man who slandered, smeared and bugged national figures and especially citizens with dissident views evidently carries no weight, either.

Three years ago, the Senate was given the chance to delete Hoover's name from the FBI building. Hoover was denounced on the floor for his longstanding secret investigation of one of the Senate's own, Quentin Burdick from North Dakota. Hoover was slammed for his secret files, his trampling upon civil liberties and his disrespect for civil rights. "J. Edgar Hoover's name on the FBI building is a stain on the building," said Sen. Harry Reid (D-Nev.), sponsor of the amendment to strip Hoover's name.

When the roll was called on Feb. 4, 1998, the vote to keep Hoover's name aloft was 62 to 36.

That says something about the Senate. It also says something about our times.

But if the Hoover name must stay on Pennsylvania Avenue a little while longer, until we come to our senses, perhaps it can be used as a learning experience for the thousands of young people who visit that building each year.

Besides finding out about the FBI's vaunted reputation as a professional law enforcement agency, perhaps the children can linger a while on that name and discover what it really represents. Through Hoover, they will come to understand what can happen to a free society when a public official begins to see himself as not just above the law but as the law itself. Through Hoover, they will perhaps learn to watch out for the public official who believes the public property he occupies and the workers who share it belong to him. Through Hoover, maybe they will see for themselves what can go awry when a bureaucrat sets himself up as the sole arbiter of what's right and wrong and as the judge of who deserves justice, and when.

Speaking of such, visiting children perhaps can learn how justice was rendered in the Birmingham case of 14-year-old Cynthia Wesley, who was decapitated, and her friends Denise McNair, age 11, and Carole Robertson and Addie Mae Collins, both 14, who were killed instantly -- and Martin Luther King Jr., who preached at the funerals of three bombing victims -- when their paths crossed the man whose name occupies a place of honor on the FBI building.

Maybe the day will come when children visiting the FBI building -- and wiser about the bureau's longest serving director -- will turn to their parents and teachers and ask: "Why is J. Edgar Hoover's name still up there?"