THERE WAS an undeniably comic aspect to

the plight of that Soviet submarine that found itself aground for a week, initially pleading radar trouble, six miles inside Sweden's 12-mile territorial waters near the country's principal Baltic Sea naval base. It is not simply that the episode evoked various delicious movie scenarios on "The Russians Are Coming" model. It is everyman's delight to see the great made humble, and there was a special pleasure in seeing a great power humbled by the sea and by Sweden alike. Even many Swedes, who were well aware of the seriousness of the incident, could laugh about it.

The seriousness of it remains. Sweden is neutral, a member of no military bloc, but it is well- armed within its means (8 million people), and it has a tradition of caring deeply about protecting itself against violations of its large land area and long island-strewn coast. The sub's penetration from the Baltic, which Soviet propaganda enjoys characterizing as a "sea of peace," amounted to the most serious violation of Swedish territory since World War II. The boat went undetected, moreover, until it got hung up. It was spying and it got caught.

The arrangement reached yesterday between the Soviet and Swedish authorities appears to have signaled the end. The Soviets huffed and puffed, but the Swedes hung in there and gained their essential point, first, by requiring the sub's skipper to board a Swedish boat for questioning, and, second, themselves dragging the boat off the rocks. The Swedes got to show the Soviet Union, on global television, that they will not be pushed around.