Abstract
This paper assesses the current state of the US federal individual taxation, and considers its recent evolution, with an emphasis on the changes to the individual income tax enacted in the 2017 Tax Cuts and Jobs Act (TCJA), and evidence on their impacts. How has the design of the tax changed, and how has this affected tax revenues, the distribution of tax burdens, marginal tax rates, and the breadth of the tax base? What were the rationales for the changes, and what does economics have to contribute to the debate over whether the changes were a good idea? What have we learned so far from empirical research on the impacts of recent changes in individual tax policy, including especially the changes enacted since 2017, and what does this imply for the optimal design of individual taxation?