Abstract
This article explores the relative impact of constituency, political ideology, and labor strength on support for presidential fast-track trade authority in 1991 and 1997. Multivariate logistic regression analysis of legislators' positions shows that constituency factors have increased in importance while political ideology explains less of the variation in support for fast-track over time. The stronger constituency basis of legislators' positions reflects both the impact of NAFTA on Democrats' stances toward free trade and the growing divide among Republicans on trade issues. Future presidential bids for fast-track authority must center on specific trade agreements and will require grassroots support to surmount congressional opposition.