I found this report by the Independent Task Force on Building a North American Community. In the Acknowledgement good old Senator John Cornyn is recognized.
http://canada.usembassy.gov/content/can_usa/northamericancommunity_TF_final.pdf#search=%22nafta%20office%20inter-american%20affAIRS%20john%20cornyn%22
On page 22 of 49 it tells why NAFTA was created for Mexico. LOL It even reports in this paragraph that the World Bank estimates that Mexico needs $20 billion a year for infrastructure and education.
Then on page 37 of 59 it suggests implementing the Social Security totalization agreement between Mexico and the U.S.
At the very top of page 38 of 59 this article suggest that none of this will work until the wages of the two North American countries are diminished to Mexicos wages.
How many Senators are still in office proud that they signed the NAFTA agreement. How many are running for reelection today?
Good find.
Move to full labor mobility between Canada and the United States. To make companies based in North America as competitive as possible in the global economy, Canada and the United States should consider eliminating all remaining barriers to the ability of their citizens to live and work in the other country. This free flow of people would offer an important advantage to employers in both countries by giving them rapid access to a larger pool of skilled labor, and would enhance the well-being of individuals in both countries by enabling them to move quickly to where their skills are needed. In the long term, the two countries should work to extend this policy to Mexico as well, though doing so will not be practical until wage differentials between Mexico and its two North American neighbors have diminished considerably.
Your interpretation of this document is entirely reasonable, since Mexican wages are indeed not coming up to the U.S. or Canadian level, that it infers that "... none of this will work until the wages of the two North American countries are diminished to Mexicos wages."