Before the end of the summer, President Clinton will ask Congress to approve the North American Free Trade Agreement linking the United States with Canada and Mexico in a free trade area comprising a population of 370 million and a gross national product of $6 trillion. It will represent the most creative step toward a new world order taken by any group of countries since the end of the Cold War, and the first step toward the even larger vision of a free trade zone for the entire Western Hemisphere.

And yet, recent polls show that barely half the American people have ever even heard of it.

This presents the president with a rare opportunity for leadership in educating the American people to the opportunity before them. Since the end of the Cold War, it has become apparent that fear of communism can no longer serve as the cement of the international order. With the collapse of the ideological challenge, traditional patterns of nationalism have gained ground nearly everywhere. The post-Cold War world has already witnessed growing rivalries reminiscent of the tensions preceding World War I.

In this light, developments in the Western Hemisphere become crucial to global order. Here, a group of democratic nations has pledged itself to the Enterprise for the Americas initiative based on popular governments and market economies. The sole dictatorship remaining in the Western Hemisphere is Cuba; state-run enterprises are being privatized; nationalistic, protectionist methods of economic management are being replaced by export-oriented economies hospitable to foreign investment and supportive of open international trading systems. The revolution sweeping the Western Hemisphere can point the way to an international order based on cooperation.

It is this revolution that is at stake in the ratification of NAFTA. What Congress will soon have before it is not a conventional trade agreement but the hopeful architecture of a new international system.

Strong presidential leadership in the ratification battle is urgently required. As the only nationally elected American leader, the president is in the best position to put NAFTA into a broad strategic framework and to show the American public why its passage serves the fundamental national interest. He must not permit the treaty's opponents to define NAFTA as a problem of economic arithmetic. In this task, the president is entitled to bipartisan support. NAFTA is so vital to prospects for global progress that it needs to transcend partisanship and merits a demonstration of nonpartisan unity.

America has never had a neighbor of the importance Mexico will acquire in the next century, with or without NAFTA. By then it will be a country with a population of well over 100 million and equal to the Asian "little tigers" such as Korea. Our de facto open borders make friendly relations a vital national interest.

Even on strictly economic grounds, I believe NAFTA to be to our long-range advantage. Most studies suggest that we would gain more jobs than we would lose -- though of course the problem with that calculation is that those who lose jobs are not usually the ones who benefit from gains in employment.

Nevertheless, let us not delude ourselves: The movement of American industry to Mexico cited by many NAFTA critics has occurred despite present tariff barriers, which are already quite low. What the critics are implying is not just a defeat of NAFTA -- which would not accomplish their objective -- but an increase in tariffs against Mexico. Such a policy would put an end to any hope of a new Western Hemisphere relationship and encourage the rise of nationalism.

For Mexico has been in the vanguard of the revolution sweeping the Western Hemisphere. Not so long ago, its foreign policy was defined by anti-American rhetoric and its economic policy by statist left-wing attitudes. Import substitution, the fashionable euphemism for protectionism, was the dominant trend, and anti-gringo suspicion a principal feature of the internal Mexican debate.

Starting with the presidency of Miguel de la Madrid in 1982, Mexico began to reverse these patterns. Under President Carlos Salinas de Gortari, the process assumed tidal proportions. Salinas turned Mexico on its head. He opened it to foreign investment, lowered tariffs, insisted on free competition, quelled corruption and brought into office an extraordinary group of young, highly trained technocrats. I know no government anywhere that is more competent.

In going all-out for NAFTA, Salinas has overcome considerable domestic Mexican reservations. He has gone to great lengths to respond to American concerns -- even to the point of negotiating side agreements on the environment and labor that his left-wing opponents describe as gringo interference in domestic legislation.

Nevertheless, to this day the ancient themes of Mexican political discourse are still just below the surface. They remain the staple of Salinas's left-wing opposition. NAFTA's defeat would cause them to boil rapidly to the surface, and would humiliate President Salinas in his bet on trust and cooperation with the United States. This would be a particular problem as Mexico gears up for next year's presidential election.

History will almost surely record the Enterprise Initiative for the Americas as one of the most important American initiatives since the Marshall Plan. It is a blueprint for which the North American trade agreement with Mexico is the vital first step for a new kind of community of nations, built on a common base of democratic values, drawn strongly together by the free exchange of goods, services and capital, dedicated to human rights and committed to the preservation of their common environment. Argentina, Venezuela and Chile have already indicated a strong interest in it. It looks far beyond the Organization of American States, the only existing institutional expression of common purpose in the region, and its outmoded concentration on national security; rather it responds to the contemporary agenda.

At a moment when all the major Latin American countries have raised their sights to a new partnership based on values the United States has been espousing for decades, a retreat from it by America would be a shattering blow to their enthusiastic response to this vision for a new and better world.

A regional Western Hemisphere Organization dedicated to democracy and free trade would be a first step toward the new world order that is so frequently cited but so rarely implemented. It would permit the countries of the hemisphere to respond creatively to any of the various ways the international order may evolve. Almost every country pays lip service to a global free trading system and to the urgency of the Uruguay round as its expression. It would be shortsighted, however, to ignore the regional groupings emerging in both Europe and Asia as possible alternatives.

A Western Hemisphere-wide free trade system -- with NAFTA as the initial step -- would give the Americas a commanding role no matter what happens. If the principles of the Uruguay round prevail, it will become a major participant in global economic growth. If regional groupings dominate, the Western Hemisphere, with its vast market, will more than hold its own in regional competition. Opening itself up to associate membership by nations outside this hemisphere could create a system for global free trade based on incentives for those willing to abide by its principles and by penalties for those nations not playing by the rules.

President Clinton has understandably preferred not to deflect Congress from concentrating on his economic package. But the stakes are too high to wait much longer. He must take the lead in defining the issues. But he should not be asked to fight this battle alone. It should be possible to enlist former presidents, secretaries of state and other leaders in one of the broad-based coalitions by which previous new departures in foreign policy -- like the Marshall Plan -- have been put before the American people.

If that happens, Clinton's will be perceived as a seminal presidency whatever else transpires while he is in office.

The writer, former secretary of state, is president of Kissinger Associates, an international consulting firm with business interests in many countries abroad.