Ross Munro is a Time correspondent who has written an arresting article in the December Commentary that makes the devilishly hard problem of American policy in the Philippines about three times harder.

Munro's piece overcomes the presumption of being loaded on the right that Commentary's political stuff inevitably bears. In "The New Khmer Rouge," he makes a case that the Philippine insurgents are not only communists but also Pol Pot communists. The distinction is important.

Everybody knows that the "New People's Army" types are communists, which means that if they won they would tend to create a police state and provide the Kremlin strategic benefit; one imagines, say, a Vietnam, or a Cuba. But if they are also communists of the Pol Pot school, they might do that and keep going: they might create a true nightmare society and kill a great many people, as in Cambodia.

Conservatives, starting with a darker view of the cosmos, will not be surprised by an analysis that comes out here. Liberals, ever more hopeful, can be expected to question his findings. Personally, I look forward to an argument. Journalism is one of the proper arenas for it.

My sense of the flow of American journalism is that there is a broad consensus, of which Munro is a part, that President Ferdinand Marcos is driving his country off a cliff but that there has been no strong focus -- just scattered factual mentions -- on the animal violence of the NPA's policy and philosophy. I would not attribute this to the usual conservative suspect, liberal bias, though in the press as elsewhere you can find some examples of a tendency to give the guerrillas the Robin Hood treatment.

There are objective difficulties of inquiry and there is in our business a natural and otherwise meritorious reluctance to say something quite far out that can't be literally proven.

From the 1970s to the 1980s the NPA notched up its terror, Munro says; it almost always takes us journalists a while to plug into changes of this hard-to-measure sort. Combing the sprawling Philippine countryside for the facts risks getting into impressionistic judgments or relying on dubious sources like the Marcos army or -- to believe Munro -- some of the communist-controlled church and human rights people. And we are often slow to read and absorb the tracts with stilted titles in which the people who are now leaders of terrible movements early on wrote down their true thoughts.

There is also a widespread presumption, and not only among journalists, that if Marcos says it -- and he does say that the NPA is a bloody bunch -- then it's probably not true.

So the inquiry is not easy, but Munro has shown a way. I hope that we of the press can be as rigorous in looking at the NPA as we are in surveying Marcos.

Meanwhile, there is no denying that the Munro findings raise the stakes of American policy. If the NPA really is a massive purveyor of terror in the Philippines right now, and if its use of terror really is the tipoff to its future design for Philippine society, then the United States has got to be extra careful about how it deals with Marcos. That's true no matter what your policy inclinations are.

Whether you would ride with Marcos or push him hard, it is one thing to do so in the expectation that if the effort fails the Philippines may become the next Vietnam. It is another if your expectation is that the country may become the next Cambodia.

The difference is perhaps more moral than political. As a public society though not as individuals, Americans seem on the way to moving beyond their defeat in the real Vietnam; it is not often near the center of political consciousness. But, I think, there is a palpable mass of lingering public guilt about the carnage that befell the real Cambodia.

Guilt is what impelled a Democratic Congress to force upon a wary Republican administration a symbolic grant of military aid to the noncommunist resistance in Cambodia last July. Guilt is what could come to concern Americans about the Philippines, a country with which the United States has had a far longer and deeper tie.

Munro suggests that the insurgents' successes have brought them to a juncture where they have to decide whether to seek large-scale outside aid. He further suggests that "if Marcos were to die or be toppled and succeeded by a competent, reformist government, it is quite conceivable that the current rapid growth of the Communists could stall."

Match up these two elements and you have a fateful race: can the Philippine government turn to reform before the Philippine guerrillas turn to Moscow? The clock is ticking.