This article uses a novel dataset, compiled from declassified records of British cabinet meetings between 1981 and 1997, to examine the motivations associated with adoption and rejection in more than one thousand policy decisions. A wide variety of motivations for policy options were considered, including those related to political calculation, institutional constraints, economic and noneconomic policy objectives, and interest group input. Dimensionality reduction and random forest models show that a narrow set of motivations related to fiscality, economic regulation, and public perceptions, were the most important predictors of the adoption outcome. Fiscal constraints and regulatory objectives were the most important predictors of adoption, and interest group demands related to fiscality and regulation the most important predictors of rejection. These findings provide support for the central role of these two core economic functions in policy adoption in a recent and influential case.