Six weeks after the invasion of Grenada, much remains unknown about the situation on that island, both as it was before Oct. 25 and as it is today. The unfolding events, clouded as they are by the Reagan administration's efforts to manage the news, have told us as much about the administration as about Grenada. They have even told us something about ourselves.
What we have learned about Grenada is that the protection and evacuation of American citizens has turned out to be more a pretext for sending troops than a reason. If it had been the reason, the troops would have evacuated the students and come home. The students are long since gone, and the troops are still there.
The troops have taken over and are running the country, much like an army of occupation. They set up an interrogation center and held and interrogated Grenadians suspected of left-wing sympathies. They closed a church-run center which was similarly suspect. In their wake have come engineers and technicians bearing American aid to repair the damage. The American ambassador is more like a pro-consul than a diplomat.
It may be that Grenada is a place where self-government simply does not work. Britain pressed ahead with independence for Grenada in 1974 in the face of opposition from the prime ministers of other Caribbean Commonwealth states, and despite political turbulence in Grenada caused by opposition to then Prime Minister Eric Gairy. Maurice Bishop overthrew Gairy in 1979 in a coup which at the time had widespread public support. But the hapless Grenadians simply exchanged one bad government for another one.
Grenada has never had a good government. Haiti, Cuba, and other Central American countries have received extensive American tutelage at one time or another with less than satisfactory results. This record does not inspire optimism about the future of American involvement in Grenada.
What Grenada tells us about the Reagan administration is at once depressing and scary. The President purportedly sought a link between the chaos in Grenada and that in Lebanon, the link being the worldwide conspiracy manipulated from the Kremlin. In this, he was committing precisely the same error as the people who see everything bad that happens as part of a CIA plot.
The President and his administration's spokesmen also seem to have revived turn-of-the-century concepts about US-Latin American relations. It was Secretary of State Richard Olney in 1895 who said, ''Today the US is practically sovereign on this continent, and its fiat is law upon the subjects to which it confines its interposition.''
The (Theodore) Roosevelt corollary to the Monroe Doctrine asserted the right of American intervention ''in flagrant cases of . . . wrongdoing or impotence.'' This view was repudiated during Hoover's administration.
Another, later version of the Olney and Roosevelt policies is the Brezhnev Doctrine, advanced in 1968 to explain the Soviet invasion of Czechoslovakia. This asserts the right of the Soviet Union to intervene to preserve ''socialism.'' This is analogous to asserting the right to intervene to protect ''freedom'' or ''democracy.''
The saddest part of this whole affair is what it tells us about ourselves. This is the willingness of people uncritically to accept what information is doled out by a self-serving government. The press is first not allowed on the island and then is hampered at every turn. Official statements turn out to be exaggerations, to use one of the gentler words. Thousands of documents are captured, but only a fraction made public.
There may, in fact, have been a situation on Grenada that warranted international concern, but the administration has not made the case unless one accepts the outdated framework in which it views Latin America. Worse, the administration has obfuscated the situation and breached the public's right to know.
And it has gotten away with it. The President soars in the polls. Republicans in Congress are adulatory, and Democrats are cowed. There is a spirit abroad in the country that we finally hit somebody. That indeed should make us pause for sober reflection.