In the past fifteen years of minimalist investigation, the theory of argument structure and argument structure alternations has undergone some of the most radical changes of any sub-module of the overall theoretical framework, leading to an outpouring of new analyses of argument structure phenomena in an unprecedented range of languages. Most promisingly, several leading researchers considering often unrelated issues have converged on very similar solutions, lending considerable weight to the overall architecture. Details of implementation certainly vary, but the general framework has achieved almost uniform acceptance. In this paper, we recap some of the many and varied arguments for the ‘split-vP’ syntactic architecture which has taken over most of the functions of theta theory in the old Government and Binding framework, and consider how it can account for the central facts of argument structure and argument structure-changing operations. We then review the framework-wide implications of the new approach, which are considerable.