COMMENTARY : ‘Frontline’ Takes a Seat at the Front : Public TV: In the shrinking black hole of television news, the PBS documentary series emerges as a shining star.

While most of television is getting dumber, some of it is getting smarter. “Frontline,” which concludes its ninth and most consistently excellent season Tuesday, seems immune from the tube’s spreading mediocrity.

As the major networks curb, cut and disembowel their news segments, “Frontline’s” reporting has grown both feistier and more developed, with a global reach few news series can match.

Its title isn’t hyperbolic: “Frontline’s” reporters have often been the advance scouts on stories ranging from the U.S. drug war to the Jimmy Carter/Ronald Reagan “October Surprise” affair, with the networks sending in their follow-up divisions later.

The networks are relevant here, because “Frontline” is one of the few programs in public broadcasting that’s actually a product of the national PBS network. While most PBS programming is produced with a mix of private funds and a single PBS outlet’s involvement, “Frontline” is a joint production of five PBS stations: Boston’s WGBH, Seattle’s KCTS, New York’s WNET, Miami’s WPBT and Detroit’s WTVS. More than any other project in public television, it represents the effectiveness of pooled resources in an era when the word cutback has become a Damoclean sword. (KCET laid off 17 people last week.)

By contrast, “Frontline,” under the stewardship of executive producer David Fanning, keeps getting bigger. It served up 24 new programs in 1990-91--the first time in the series’ nine years that the season stretched from September to June--and there was rarely the sense that a report was being slotted merely to fill a hole: Each documentary, weak or strong, reflected a drive to have the story told. Usually, that compulsion--the oil, after all, of investigative reporting--stemmed from the personal outlook of the reporter, which is one reason why “Frontline” has tended to avoid the institutionalized feeling of so much public-affairs television.

For instance, Ofra Bikel’s “Innocence Lost” last month, about an Edenton, N.C., child-abuse scandal with disturbing echoes of the McMartin preschool debacle, was more than anything the result of Bikel doggedly staying with her subject for many months, thus gaining the confidence of people to open up in ways they never would with a news crew blowing through town.

Bill Moyers’ “High Crimes and Misdemeanors” in April was never the perfunctory wrap-up report on the Iran-Contra scandal that it could have been (the other networks have long ago, and with no explanation, put this major chapter in the Reagan years to rest). Instead, it was Moyers’ own search, through political hallways he trod during his stint in the Lyndon Johnson White House, of the causes for what he described as crimes against the Constitution.

Because of the presence of people like Moyers and Hodding Carter (who worked for another Democratic President, Jimmy Carter), such passions are viewed by some as passions of the political left. A letter to this critic, in response to “Frontline’s” examination of the U.S. invasion of Panama: “Once again, we have the left-wing staff of ‘Frontline’ attacking the United States with distortions and exaggerations.”

Look again. Since it aired during the Persian Gulf War, one might have thought that “Frontline’s” “War and Peace in Panama” would have paralleled both operations. Were “Frontline” deep in the left wing, it would have insisted on showing how the attack on Panama’s Noriega was a dress-rehearsal for the attack on Iraq’s Hussein. The purpose of the report wasn’t to toe a political line, but to show Panama’s pathetic reality.

That can make the right and the left itchy, and “Frontline” also does this consummately. No more devastating examination of the corrupt underbelly of Fidel Castro’s Cuban regime has ever aired than the February program “Cuba and Cocaine.” In its thorough insights and resolute conclusion that Castro is just another money-grubbing dictator, it dashed for all time any remaining shards of the symbol of “Fidel.”

And for every episode that gave U.S. foreign and domestic policies the third degree--you could almost hear the embarrassed sighs coming out of CIA headquarters when “Frontline” aired Tom Mangold’s stunning “The Spy Hunter” last month--there was an episode that confirmed the right’s favorite mantra that “the world is a dangerous place.” Hodding Carter’s study of “The Mind of Hussein” in February finally made The Enemy more comprehensible, and scarier than ever.

Most important, perhaps, “Frontline’s” ninth season seemed to be more out in front of the news than in seasons past. Does anyone seriously believe that the Big Three would have spent the time and precious resources tracking down the truth behind charges that Reagan’s 1980 campaign staff finessed a deal with Iran to delay the hostage release until after the November election? Whether by accident or effect, after “Frontline” aired “The Election Held Hostage” in April, a string of rumors became a story that is making headlines everywhere.

The major media outlets obviously keep an eye on “Frontline,” just like any NBA pro is going to keep an eye on Magic and Michael. But there has to be some underlying envy of a relatively small news outfit that can, without visible strain, give you a rich portrait of the Amazon rain forest one week and state lottery operations the next--and find the deeper meanings behind both. That envy is likely to persist as long as “Frontline” continues to do what it does with tough-minded consistency.