OFFICIALS OF the Immigration and Naturalization Service have now completed an investigation of the incident in which two border patrolmen returned a Soviet seaman, Miroslav Medvid, to his ship. They recommended that the agents be demoted in rank and suspended without pay for 45 and 90 days. What are the general rules, anyway, and how should the Border Patrol have responded in this instance?

About 15,000 foreigners seek political asylum in this country each year. These include migrants from Central America, touring artists and sports figures from communist countries, and innumerable ship-jumping seamen from all around the globe. Each has exactly the same rights under the law to apply for political asylum and to have his case adjudicated in a hearing and on appeal. The rule is that neeking asylum is ever returned to his homeland against his will until all his legal remedies have been exhausted.

Twice in the past five years, a person seeking asylum has been, through administrative error, sent home before legal review was complete, but in both cases the United States sought and won his return to this country.

Under INS regulations, asylum requests filed by citizens of certain countries -- primarily the Soviet bloc and China -- are treated on an expedited basis. The explanation is that this is necessary so that if the decision is adverse, the person has a chance of returning home within a few days, perhaps before his government knows he has tried to leave, since these countries have a well-known history of punishing citizens for the simple act of trying to leave; most other countries do not.

The Medvid case should have been handled in this manner. A preordained series of phone calls -- to supervisors, to INS in Washington and to the State Department -- should have been made immediately. The trouble in this case is that the border patrolmen maintain they were told by a translator that the seaman did not want asylum. Whether this was due to a foul-up in translation, a bad phone connection or the heavy accent of the translator is not known. Moreover, the officers turned Mr. Medvid over to local agents of the Soviet ship and were not even present when his struggle and second leap into the water took place. American officials later took him back ashore; by this time ship officials had talked to him, and he insisted he wanted to go home.

It was a serious failure of judgment not to have been especially careful with a Soviet seaman. There was reason to be skeptical of the long-distance translation. The border patrolmen were slow to seek the advice of superiors. For this the patrolmen are being punished. As a general rule all persons seeking asylum here are given every opportunity to make their case and to remain here while they do. That is the way it should be.