There are many lessons to be drawn from Mexico's successful election. The most important one for U.S. policymakers is this: To deepen democracy in our hemisphere, we must resolve our domestic debate about the appropriate terms for trade and extend the North American Free Trade Agreement throughout the Americas. The much-derided NAFTA is the unsung hero of Mexico's peaceful democratic revolution.

For most of the last century, Mexico's nationalistic ruling party, the PRI, jealously guarded the nation's "sovereignty," and declared its domestic politics off limits to outside scrutiny.

But in 1994, when Mexico agreed to open its economy to free trade and investment flows from the United States and Canada, it also opened up the nation's internal politics to the scrutiny and standards of the larger, democratic community. The PRI understood that it could not attract new capital, technology, plants and equipment from the developed democracies while at the same time shutting off its internal policies. In the ensuing years, opposition political forces took full advantage of the electoral and press reforms that the PRI began to institute, and in 1997 captured the lower house of congress for the first time in Mexican history.

On Election Day 2000, with the "whole world watching" in the form of international observers and press, ordinary Mexicans sensed that even if the ruling party wished to do so, it could not risk the international firestorm -- and outflow of investor dollars -- that would have resulted had it tried to steal the election. With the confidence that for the first time their votes would count, and less fearful of official retribution, Mexican citizens turned out in record numbers to evict the ruling party.

When the United States was moving forward, after NAFTA's ratification, to expand free trade throughout the Americas, it set off a competition among nations in Latin America and the Caribbean to reform their economies and clean up their politics to get to the head of the line. The hemisphere understood that Chile was designated by both the Bush and Clinton administrations to be the first to join NAFTA, not just because it had led the process of market opening but also because it had carried out a successful transition from military dictatorship to electoral democracy. But after Congress refused in 1997 to grant the Clinton administration "fast-track" authority to negotiate with Chile, the momentum for market reform, and also democratization, diminished in Latin America, and so did U.S. leadership.

The United States needs to have a long-overdue domestic debate about the terms of expanded trade in the hemisphere. Critics of the NAFTA agreement ask: If intellectual property rights must be respected as a condition of expanding trade, why not also labor rights and environmental safeguards? The question deserves an answer. Labor rights have been part of trade agreements almost since their inception: The General System of Preferences is tied directly by law to a nation's safeguarding the right of trade unions to organize freely. Those who advocate such changes also bear a burden: to prove their goal is to improve trade agreements, not make them impossible to conclude. The two leading U.S. presidential candidates, both of whom supported NAFTA, ought to be leading such a debate.

But critics who claim that free-trade agreements such as NAFTA strengthen ruling political elites against the interests of ordinary citizens misread the hemisphere's history. Traditionally, powerful family groups prospered in Latin America's former closed economies by currying favor, often corruptly, with politicians and ruling parties, who would, in return, erect tariff barriers against competitors, issue preferential regulations and award lucrative licenses and contracts. Opening up those economies to competition and scrutiny breaks up those nests of entrenched power and liberates opposition forces to press for democratic change.

Mexicans voted in record numbers not just to end 71 years of authoritarian rule: Eighty percent of them voted also for candidates who supported NAFTA, which helped make that vote possible.

(Aronson was assistant secretary of state for inter-American Affairs from 1989 to 1993)