One of the excuses given for showing "Death of a Princess," the controversial British docudrama, on stations of the Public Braodcasting Service (PBS) tonight is that it will allegedly shed new light for Westerners on the mysterious world of Islam.

After viewing the program at the center of all the hullabaloo, however, one may justifiably wonder if lighting one little candle is always really better than cursing the darkness. About the only thing to be gleaned from this impossible coy and confused shell-game of a movie is that the Mideast remains inscrutable and that women have a hard time there.

It's truly ironic that the film whose telecast has generated probably the biggest flurry of protest in public TV's history here is exceeded in its presumptuousness only by its tediousness. The two-hour movie, at 8 tonight on Channel 26, is nothing more than a series of dramatized interviews conducted by a British journalist investigating the execution of a 19-year-old Saudi Arabian princess and the young man with whom she was believed to have committed adultery.

The film might have passed quietly into the singular netherworld of public TV obscurity if the Saudi Arabian government hadn't become exercised about its broadcast (as it did when the film was shown in England), hadn't had the unforgivable gall to pressure PBS against showing it, and if the corporate state known as Mobil Oil, hadn't invested some of its outlandish profits in campaigning against the showing of the film with big newspaper ads.

The incident depicted in the film is supposed to be resonant with implications about Islamic culture, its isolation, the way it inhibits women, its sexual codes, and so on. The incident that the film has become is a far more illustrative one, however, since it points out the precarious high wire act that public broadcasting has to walk in this country, mainly because the apparatus that funds it has never been made stable nor sufficiently safe from the grasp of government.

A Houston judge, for instance, has ordered a reticent public TV station there to show the film as scheduled on the grounds that the station is a government entity and that to preempt the program would be government censorship. But if not showing the program is an official statement, so is showing it, and the Saudis then have a good case for being indignant. Public TV cannot survive half-slave and half-free, and if the mess engendered by "Death of a Princess" makes that more graphic, then the program will have served the only purpose it appears capable of serving.

As far as aftermath goes, we can expect official protests and official apologies and not much else. That is partly because the film itself has no emotional power; it's less a rabble rouser than a rabble drowser. It's eye-witness snooze, inert as drama and inadmissible as investigative journalism.

Filmmaker Antony Thomas, who directed the script and co-wrote it with David Fanning, reputedly spent 18 months researching the story and interviewing those close to it, though not anybody who could justifiably be called a participant. From those interviews, recorded on audio tape only, he might have fashioned a solid magazine piece or a radio documentary.

Instead he chose to commit the ultimate exercise in ersatz; having actors play the people interviewed, changing virtually all the names involved including his own, and filming the interviews in such a way that, despite disclaimers, people tuning in late might think they are seeing something real. One actress, playing an older princess, is even photographed in shadow to conceal her face.

Any audience attracted to the program by all the attendant hysteria will probably be quickly dispersed -- say, in the direction of "Lou Grant," where the versimilitude is less ploddingly out of the starting gate. The director himself has called it "a heavy two hours of discussion," and there are only about 10 very visual minutes in it.

The reenactments of the executions themselves come fairly early, during a flashback from an alleged eyewitness, and the rest of the film consists of an actor playing the journalist pretending to interview actors playing interviewees about a year after the incident took place.

To be sure, issues are raised -- culture clash, ethnocentricity, Westerization of Easter societies, royalty as anachronism, changing sexual roles. An Arab friend of the journalist asks him early in the film, "How much of our past must we abandon? How much of your present is worth imitating?"

Much later, a teacher at a Saudi girls' school demonstrates, in her remarks, how technological tools of the 20th century can be used to reinforce strictures that go back centuries. Girls are allowed to privilege of male instructors only when the men appear to them on classroom television, and they can converse with those instructors, but only by telephone.

In Beirut, the writer travels through a war-torn city and looming above veritable ruins is a veritably decaying old Pepsi-Cola sign. The princess who was executed (a magnificent vision, in brief flashbacks, played by Suzanna Abou Taleb), is described as "a girl who challenged the system," and the writer comes to believe that "her story's tied up with everything else" in the culture.

But the film seems too heavy-handed in discovering alleged hypocrisies and paradoxes in the Islamic world, almost appearing to say that none exist in, oh, England, for example. In a bar, the writer is advised by one Arab he has asked about the princess and her lover to "leave it alone . . . just leave it alone," and it's a pity Thomas didn't take the advice, or at least find a more congenial forum for his self-righteous pilgrimage.

The progress is so slow and the parade of interviewees so tiresome that eventually you begin noticing that the interviewer usually does his genteel reportage over lunch, or drinks, or dinner. By the end of the two hours, he should have gained about 25 pounds. Our hungry journalists. Of course, "Death of a Princess" is not journalism at all, nor drama, nor even very good docudrama. It's a shame that a public TV cause celebre has turned out to be a stultifying sham.