It was a long way from Versailles, France, to Williamsburg, Va. The year that intervened was a sobering one for the world economy. Not only did Western leaders find themselves in disarray after Versailles, scrapping about what it was they actually had agreed to, but they soon discovered they had a Third World debt crisis on their hands that threatened the stability of the banking system and, with it, the global economy.

The possibility Mexico might default on its international debt galvanized world leaders into action last summer. The Federal Reserve Board backed smartly away from its monetarist approach, which was fast turning recession into depression.

The wheels also began to turn--very slowly at first--at the International Monetary Fund meeting in Toronto last September, leading to an expansion of temporary financial resources for the hard-pressed debtor nations.

Meanwhile, efforts were launched to repair the damage done at Versailles over East-West trade relationships. Here, Secretary of State George Shultz played an important role in defusing tensions.

In February, the major nations gave their approval to a boost in the IMF's regular lending resources, and a legislative effort to put that through Congress is still under way.

Then, early in May at the meeting of 24 industrial nations at the Organization for Economic Cooperation and Development in Paris, their foreign and finance ministers reached an important conclusion: even though inflation was still a problem in several nations, the time had come to stress economic growth. Without a concerted effort to increase buying power throughout the Western world, unemployment in rich countries would grow, and poor nations, struggling to pay off their debt, would find their export markets in the West shrinking even further.

If that happened in Third World countries, then their ability to buy goods from the richer nations would also shrink, with obvious implications for jobs in the richer countries. In fact, the process is already under way. Brazil and Mexico, two of the United States' largest customers, have already sharply curtailed trade with America, at a cost in jobs not yet fully measured, and certainly not yet appreciated on Main Street--which is worried more about Japanese competition.

Such has been the backdrop for this ninth economic summit. For that reason, President Reagan and all of the other world leaders present exhibited good will, a willingness to compromise and a determination not to have a repetition of Versailles.

The result was that there was an extraordinary sense of cooperation here at Williamsburg that will allow the summit process to survive, even though many of the differences remain. "What is important is that all of the participants agreed to add the necessary degree of confidence in the upcoming recovery," said Count Otto Lambsdorff, the West German economics minister who has bridged the transition from Helmut Schmidt to Helmut Kohl.

To be sure, summit communiqu,es are a bit vague, and the Williamsburg Declaration is no exception. But as Treasury Secretary Donald Regan observed, he and his fellow finance ministers have been instructed by their political bosses to work together, to try to halt the protectionist surge and to give "special attention" to the international debt and other problems of the Third World.

They also agreed, as Regan put it, to "start a process" to see whether there should be an international monetary conference, as urged by French President Francois Mitterrand, to reshape the international monetary system. That should not be confused with an actual call for a new Bretton Woods.

But a willingness to at least sit down, as the finance ministers and the IMF are now directed to do, and see how the problems of economic growth, trade, debt and exchange rates are interlinked could be a big step forward.

It is easy to be critical of summits, often used by participants, as this one was used by Margaret Thatcher, for scoring points at home. But the larger view, which I share, is that national governments can no longer take actions without attention to the impact on others.

The past year taught governments that they must "give a damn" about the impact of their actions on others. And the need for a collective approach is probably acknowledged more fully in the Williamsburg Declaration than ever before.

But it is essential that the nations involved take specific actions quickly to reinforce their promises, such as the anti- protectionist pledge here. It has become fashionable to approve protectionist schemes, with or without the protectionist brand name.If the summit leaders want to be taken seriously, they will have to show there is something more than words to the Williamsburg Declaration.