The soundbite version of Kerry's trade policy is:
Make Trade Work for America. The Bush Administration has neglected to enforce trade laws or respond to the unfair practices of some of our nation's largest trading partners. As President, John Kerry will: order an immediate 120 day top to bottom review of all trade agreements to ensure that foreign nations fully comply with trade agreements they sign with our country; vigorously enforce our trade laws to ensure our workers are not victims of unfair trading practices; insist future trade agreements incorporate within them core labor standards and environmental protections; demand that other countries, such as China, do not manipulate their currencies to gain unfair trade advantages; and help any workers displaced by trade develop new skills and find new jobs.
http://www.johnkerry.com/pressroom/releases/pr_2003_0828.html
I do know that Kerry has talked about using the Jordan-US Free Trade Agreement as a model. This agreement is the first enacted that does include environmental and labor provisions. Is it perfect -- no doubt not. The first try never is perfect.
Under Article 6 of the FTA, the United States and Jordan reaffirm obligations under the International Labor Organization and their obligations under the International Labor Organization’s Declaration on Fundamental Principles and Rights at Work and its Follow-Up.
The United States and Jordan agree to not relax domestic labor laws to encourage trade. Additionally, both countries agreed to ensure that laws for labor standards comply with international recognized labor rights. The FTA does not address any new labor laws or commitments.
http://www.jordanusfta.com/overview_labor_en.asp
Article 5 of the FTA addresses the issues of environmental laws. Seeking to protect and preserve the environment, each country affirms that neither will waiver or relax their current environmental laws. Furthermore, the country agrees to “provide for high level of environmental protection and to strive to continue to improve“ their environmental laws.
The United States and Jordan also issued a Joint Statement on Environmental Technical Cooperation. Under the memorandum, the United States and Jordan will establish a Joint Forum on Environmental Technical Cooperation, which will regularly discuss environmental priorities, and to work jointly to enhance levels of environmental protection.
http://www.jordanusfta.com/overview_trade_related_environment_en.asp
On NAFTA, Kerry's amendment would have ensured that foreign investors have no greater rights than US citizens under the US Constitution. It was defeated.
http://www.sierraclub.org/trade/fasttrack/kerry_amendment/But I don't think that is what you are asking about... could you be more specific?