This article examines why and how environmental activists, despite considerable
political weakness and disproportionally few resources, won substantive negotiating
concessions that far outstripped labor achievements during NAFTA’s negotiation.
Despite a trade policy arena hostile to their demands, environmentalists gained official
recognition for the legitimacy of their claims, obtained a seat at the negotiating table,
turned a previously technocratic concern into a highly visible populist issue, and won an
environmental side agreement stronger than its labor counterpart. We argue that this
unexpected outcome is best explained by environmentalists’ strategic use of mechanisms
available at the intersection of multiple fields. While field theory mainly focuses on
interactions within a particular field, we suggest that the structure of overlap between
fields—the architecture of field overlap—creates unique points of leverage that render
particular targets more vulnerable and certain strategies more effective for activists. We
outline the mechanisms associated with the structure of field overlap—alliance
brokerage, rulemaking, resource brokerage, and frame adaptation—that enable activists
to strategically leverage advantages across fields to transform the political landscape.