The relationship between the United States and the Soviet Union was hit by a sudden, violent event last week, and - to the surprise of many - it came through almost unchanged.
Angry and lurid words were exchanged. President Reagan called the shooting down of a Korean airliner a ''massacre.'' The Soviets alleged that the plane was on a spy mission and the affair had been rigged by Washington to destroy Moscow's ''peace initiative.'' Secretary of State George Shultz met Foreign Minister Andrei Gromyko in Madrid and called his explanation of the shooting ''unacceptable.''
But the negotiating teams from the two countries went to Geneva on schedule to resume talks on arms control. And Mr. Reagan was quick to announce that the new agreement just signed with the Soviets for sale of grain and the lifting of a ban on the sale of pipeline equipment would be honored.
Some of the President's conservative constituents clamored for a break in diplomatic relations and a total ban on all trade and on all technical and cultural intercourse.
But as the dust settled, the most the White House had done to punish the Soviets for the deed was to delay plans for a new cultural and consular agreement and to refuse to renew a transportation agreement.
The fact that so little in the way of reprisals was done is remarkable in view of the nature of the deed. The Soviets had shot down a scheduled passenger airliner with 269 persons aboard, of whom more than 50 were Americans. All perished.
This was the largest loss of life yet in the shooting down of passenger airliners for alleged violation of national airspace. The previous largest loss of life in this sort of affair was 108 lost when Israeli fighters shot down a Libyan airliner in 1973.
The restrained reaction in the Korean tragedy is also remarkable in terms of the deep and emotional anticommunist attitude of the White House. No previous US administration has consistently applied to the Soviets such epithets as ''an evil empire'' and the main ''source of violence'' in the world.
That the deed was brutal and unnecessary (US ''spy'' satellites routinely see anything inside the Soviet Union which people aboard a wandering airliner could see), and that the Reagan administration is reflexively anticommunist and anti-Soviet, shows that the ties that bind the two superpowers of today's world are stronger than the forces pushing them apart.
The strongest tie is mutual interest in avoiding nuclear war and, if possible , abatement of the cost of the arms race.
Both Washington and Moscow have recognized for years that there is, in fact, no such thing as winning a nuclear war. Both know that the ultimate catastrophe for both would be to allow their differences, which are manifold, to escalate into a nuclear exchange.
Both Washington and Moscow also feel the burden on their respective economies of the arms race, which is piling up vast arsenals of the most expensive weapons ever conceived, which, if common sense prevails, will never be used.
Hence, in spite of the brutality of the deed and of the deep dislike of both governments for each other, they will continue the search for a possible agreement on arms controls.
Contributing to the larger reason for carrying on with East-West business almost as usual is the practical matter for Washington of grain sales. Washington must have the Soviet market for its surplus grain or see the price of grain plunge to levels US farmers would regard as intolerable.
As a practical matter, the US government must export grain to the Soviet Union or buy it up. And its granaries are already bursting with leftover surpluses from other years.
Undoubtedly there will be a phase of more than usual frostiness in US-Soviet relations. Tourism may decline for a while. There is already some boycott of Soviet goods. But considering that Soviet exports to the US (mostly chrome and vodka) are so low in value that most trade tables don't bother to list the figure, this will be no serious loss to the Soviets.
Certainly the US, along with other countries, will press the Soviets for agreement on new rules to reduce the possibility of passenger airliners being treated as hostile intruders.
But the affair discloses one thing above all else. Although both the US and the USSR dislike each other profoundly, and each seeks to undermine the other, they both know that they live on the same planet and can destroy the other only at unacceptable cost.
This is coexistence.
It goes on in spite of the downing of the Korean airliner and the President's calling the Soviets ''liars,'' and the Soviets' accusing him of devising the affair for his own political purposes, both domestic and international.
It will probably undermine to some extent the ''peace'' movement against deployment of new US weapons in Western Europe and help the President get the defense spending he wants from Congress.
It might prod both Washington and Moscow toward new agreements aimed at reducing the danger of crises escalating into nuclear war. But of course it will not usher in any new era of goodwill between Moscow and Washington.
But we know from last week's shooting affair that they both recognize that they must, no matter how much they dislike it, continue to coexist on the same planet.