In recent weeks, voters have forced candidates for the Democratic and Republican presidential nominations to address America's economic relationship with Mexico and Canada and the entwined issues of trade and immigration. At an AFL-CIO sponsored candidates' forum in Chicago on Aug. 7, the Democratic contenders were asked if they would scrap or fix the now 13-year-old North American Free Trade Agreement. Republican candidates have faced questions on the campaign trail about a so-called "NAFTA superhighway" being planned to link Mexico with the American Midwest.

Concern about NAFTA from across the political spectrum will be further stoked by a meeting today and Tuesday between the presidents of the United States and Mexico and the prime minister of Canada to discuss the future of North America. The Three Amigos summit agenda will be dominated by a NAFTA-plus strategy dubbed the Security and Prosperity Partnership. Two previous summits devoted to the partnership featured extensive consultations with the North American Competitiveness Council, whose core members include Wal-Mart, Lockheed Martin, Chevron and General Motors - the same corporate interests that have most benefited from NAFTA.

Rather than tackle the problems at the root of the NAFTA model --growing income gaps and worker insecurity in all three countries, as well as dramatically accelerated migration from Mexico to the United States -- these leaders and their corporate allies hope to extend its reach.

It would be easy to dismiss the summit as just another gathering of heads of state if there wasn't so much at stake. According to the Economic Policy Institute, income disparities between and within the NAFTA partners have grown during the years since its implementation. That damning reality is central to understanding the immigration debate that has gripped the United States this year.

According to the Pew Hispanic Center, the number of Mexican migrants to the United States has doubled between 2000 and 2007. Fifty-six percent of undocumented immigrants in the United States were born in Mexico.

While both Mexican and American leaders and their elite business allies promised NAFTA would decrease immigration from Mexico to the United States, free trade has cost many Mexicans dearly. More Mexicans live in poverty now than in 1994 when the minimum wage could buy more than 44 pounds of tortillas. Today, at approximately $4.20 a day, the minimum wage buys just seven. As opportunities have faded at home, many of Mexico's best and most energetic young men and women have followed the dictates of the free market and sought better options elsewhere.

Migrants' survival instincts and aspirations have collided with the contradictions of the NAFTA economy. On the one hand, we have open borders for trade and investment; on the other, growing legal and physical barriers aimed at excluding, punishing and deporting a worker population that is essential to the American construction, agriculture and food services industries.

These contradictions go a long way in explaining why the attempt to extend NAFTA's reach has been developed behind closed doors. Opening the process might force Presidents Bush and Felipe Calderón to acknowledge that by artificially divorcing continental trade and investment policy from labor and immigration policy, they are feeding the forces that drive our seemingly intractable immigration dilemma.

Designing labor and trade policies with public input would be a better way forward for North America. In the wake of the failed immigration reform efforts in the United States this year, it is clear that any effort to rationally address immigration flows and humanize American policies lies in tackling the desperate need for sustained community-level economic development in Mexico.

At their summit, the presidents and the prime minister could begin a change in course by delaying the removal of tariffs on white corn and beans from the United States to Mexico scheduled for the beginning of 2008. Such a move would provide some protection to Mexico's most vulnerable small farmers, the very people who make up a substantial portion of the migrants to the United States. Investing in Mexico's communities will provide opportunities for Mexicans to stay at home and reduce the pressures currently overwhelming the U.S. immigration system.

Chances are a conversation about genuine prosperity and human security in North America will not come from the summit leaders. For that reason, the connection between trade and immigration belongs squarely on the electoral agenda of both the Republican and Democratic parties. That debate is one the American people - left and right - will likely have to generate from below.

Ted Lewis is the Mexico Program Director for human rights group Global Exchange (www.globalexchange.org).