The U.S. labor share of income has been on a secular downward trajectory since the
beginning of the new millennium. Using data that are disaggregated across both state and
industry, we show the decline in the labor share is broad-based but the extent of the fall
varies greatly. Exploiting a new data set on the task characteristics of occupations, the U.S.
input-output tables, and the Current Population Survey, we find that in addition to changes in
labor institutions, technological change and different forms of trade integration lowered the
labor share. In particular, the fall was largest, on average, in industries that saw: a high initial
intensity of 'routinizable' occupations; steep declines in unionization; a high level of
competition from imports; and a high intensity of foreign input usage. Quantitatively, we find
that the bulk of the effect comes from changes in technology that are linked to the automation
of routine tasks, followed by trade globalization.