THE STATE television in South Korea, expecting little to come of it, recently arranged a show to let members of separated families search for each other on the screen. Korea has an extraordinary number--in the millions--of such families, split first by the social eggbeater effects of the Korean War and kept divided since either by the hostility between the two Korean states or by the difficulty of tracking members within South Korea proper. As it happened, through television, a relative newcomer to the averge Korean home, tens of thousands of South Korean families reached out as though released from a long emotional freeze. Nearly 2,000 reunions of the most painfully joyous sort were consumated, and the program is to continue.

But this procedure addresses only the lesser part of Korea's immense social wounding--the part involving Koreans who live in the South. It still is not possible to bring together families separated by the 38th Parallel. Of the four countries left divided by World War II and its aftermath--China, Germany, Korea, Vietnam --Korea is alone in having maintained not only political hostility between its two parts but also an air-tight separation barring contacts of any sort.

South Koreans have repeatedly tried to bridge the family gap. But the communist North Koreans, seeing in the effort an opportunity to apply political leverage for their one-sided approach to national reunification, have refused to allow any contacts: not an exchange of names, not pictures, not letters, not phone calls, not visits, not emigration--a policy of cruelty blighting the lives of millions.

As a result of the explosive success of the South Korean television show, the country's Red Cross has suggested a joint South-North television project to search for members of war-divided families. If North Korea had a leadership with the slightest concern for the deepest feelings of its citizens, it would leap to take part. Nothing explains better than its refusal why it is a pariah state.