When a family is in trouble, it is natural for it to draw the wagons around and tend to its own. Nations are no different. Instinctively, when faced with a threat to their well-being, they tend to withdraw into themselves and to protect first their own citizens. Yet, with the whole world in recession, what is urgently needed is not a turning inward but a thrust outward - a greater cooperation among nations to spur a revival of global growth.
Trade is the key to that growth, and much progress has been made in recent years to promote it. As a result, living standards have risen markedly in both the industrialized and the developing countries. But that progress is in danger of being curtailed as nations, confronted with high unemployment, scurry to guard their own turf. This is why World Bank president A. W. Clausen is persuaded that, if the world economy is to be energized, the United States - with the weightiest economy - will have to exercise vigorous leadership on global economic issues.
How well is it doing?
Certainly the Reagan administration recognizes the fact of global interdependence, the need to compete effectively in the world, and the desirability of widening the rules of trade. But there are some disturbing trends - on both the trade and aid fronts - which have to be turned around if the US is to play that dynamic role urged on it:
* The winds of protectionism in the US Congress are too strong for comfort. The House of Representatives has just passed ''domestic content'' legislation which would require foreign automakers to use specific percentages of US parts and labor for cars sold in the US. Fortunately, the Senate is not likely to act on the bill in this lame-duck session. But it does raise legitimate concern about sparking a trade war.
Admittedly, American auto workers would obtain some short-run gains from such a measure. But in the long run the US economy - and every other economy - would suffer. For many decades Americans could make do without world commerce, and so they may not yet realize how essential trade has become to their well-being. Exports accounted for 27 percent of all the growth in US civilian employment between 1977 and 1988, Mr. Clau-sen told the World Affairs Council of Boston.
Means must be found to ease the distress of US industries and workers hurt by foreign competition. But the way to growth lies not through clinging to the old , but through introducing new products, developing new industries, learning new ways of trading.
* The US is not doing as well as it might in providing foreign aid. Here, again, the temptation is strong in time of recession to cut back the flow of help to others and look after those at home (who, even so, are not being helped all that much). But it takes vision to recognize that the only way the United States and the other industrialized nations can expand their own economies is to help the developing countries expand theirs - and dig out from under the present crush of debts. Almost 40 percent of all US exports go to the developing countries, a figure bound to rise as the third-world economies grow stronger.
Yet it remains a blot on America's overall generous record that it is not meeting earlier commitments to foreign aid giving and above all to the International Development Association (IDA), the arm of the World Bank which grants zero-interest loans to the poorest countries and has put such nations as India on the path to sturdy growth. Notwithstanding IDA's successes, the US slashed its contributions in the last fiscal year, stretching out over four years the payments that were to have been made over three. It is only because other IDA donors are generously making up the American shortfall that IDA can maintain its credit volume through fiscal 1984.
If there were a good reason why the US has to cut back its aid - and it is now 16th among the rich countries in aid giving as a percentage of GNP - that would be one thing. But when US defense spending is rising at roughly 15 percent a year, something is wrong with the balance of priorities. Indeed the whole world is now estimated to be spending about $600 billion a year on arms - ten times as much as on development aid.
This is no call for disarmament. It is a call for an understanding in Washingon and among all Americans that they are living in a different world today - a world in which it is not possible to go it alone. They are, more and more, members of a global family and, as the strong elder brother, must assume the responsibilities that membership demands.