Competing for the votes of industrial workers during last Spring's Democratic Party primary, both Barack Obama and Hillary Clinton pledged to renegotiate the North American Free Trade Agreement in order to add protections for workers and the environment. The idea was immediately dismissed by the political classes in the US , Mexico and Canada as excessive campaign rhetoric that would soon be forgotten. And indeed, both Obama and Clinton later seemed to back away from their own words.

But the meltdown of US financial markets is going to undermine the assumptions upon which US -- Mexico economic relationships since NAFTA have been based. The result may be an opportunity not just to amend NAFTA around the edges, but to re-envision a North American economy that works for the vast majority of people in all three countries, rather than the elites who originally negotiated it.

NAFTA was the prototype for the network of neo-liberal economic agreements that now encircle the globe. Under the cover of "free trade" it undercut the capacity of the people of each nation to decide their own policies for investment, intellectual property, finance, procurement and other instruments of economic development. In essence, NAFTA is the constitution for a continental economy that promotes the bargaining position of just one class of market participant -- the multinational corporate investor.

Thus, it should be no surprise that income and wealth has shifted from the working to the investing class across the continent. In all three nations real wages (adjusted for inflation) have fallen behind the increase in labor productivity, with the difference going into the pockets of those who own and manage corporate business.

The promise that NAFTA would generate sustained high levels of prosperity for ordinary Mexicans was of course an illusion. But the social and political impact has been cushioned by the continued US economic growth that allows Mexican elites to export a share of their poverty and unemployment to the US . The situation benefits the rich and powerful on both sides of the border. Mexican elites get rid of frustrated, ambitious workers who might cause political problems at home. At the same time they profit from the hard currency remisas into the Mexican economy. US businesses benefit from a new supply of cheap labor.

But US growth of the past 20 years has itself rested on an illusion. i.e., that Americans could continue forever buying more from the rest of the world than they were selling and financing the trade deficit through borrowing at low interest rates from foreigners. These lenders were willing to recycle credit back to the United States because they trusted the integrity of Wall Street institutions, the competence of those who managed them and the stability of the USZ dollar. That faith has been seriously weakened, if not shattered.

Even if the $700 billion Wall Street bailout succeeds in calming the credit markets, the US economy is headed for a long period of retrenchment. It will be a decade or more before the housing market recovers sufficiently for consumers to use once again rising prices to finance their consumer spending. Interest rates will be higher. Highly indebted American consumers whose paychecks have been stagnant for two decades will now be forced to live within their means, saving more and spending less, especially for imports made more expensive by a weak dollar. To close the trade deficit, the US will have to export more, but with so many industries already gone off-shore, Americans will be forced to compete on the basis of lower wages. The costs of the bailout, the military empire and shoring up deteriorating health, education and pension systems will mean higher taxes and reduced government services -- and falling living standards for the average American family. Among other consequences, hostility to immigration is likely to continue to harden, cutting off the immigration safety valve that has so far relieved social tensions within Mexico .

The era in which debt-fueled US economic growth could continue cover up the failure of NAFTA's promises is over. Still, the integration of the North American continent cannot be reversed. There are too many economic, financial and personal links among the three nations to separate them. So it is time to go back to the drawing board.

It is not impossible to imagine a different vision of a North American economy. One in which human rights, community stability and economic justice take priority over the rights of capital to oppress all three in the name of private profit. But it is impossible to imagine such values being negotiated by the same class of cross-border elites that brought us NAFTA.

Resistance to NAFTA has long existed in all three countries among small farmers, trade unionists, environmentalists and ordinary citizens revolted by the inequality and social disintegration that the economic integration has promoted. But unlike the political partnerships among the continent's elites, they have not created serious cross-border political alliances. By themselves they are isolated and cannot succeed. Thus, for example, when Mexican farmers demonstrated for a revision of NAFTA's agricultural chapter, the US and Canadian ambassadors dismissed them with contempt. Had the farmers been supported by US and Canadian trade unionists and environmentalists, it would have been harder for the Mexican government to stifle their demands.

Building a cross-border political alliance of the Left will not be easy, especially since many of the anti-NAFTA constituencies in all three countries have in part made their case with nationalist arguments. But as the economic foundations of the neo-liberal constitution of the North American economy continue to crumble, there may be an opportunity for a continent-wide popular movement to challenge the corporate class with a different and more appealing vision of North America 's future.