As a background paper to Jayadev and Bowles (2006), this paper provides details on our measure of guard labor as we measure these in labor units. Data from the United States indicate a significant increase in its extent in the U.S. over the period 1890 to the present. Cross-national comparisons show a significant statistical association between income inequality and the fraction of the labor force that is constituted by guard labor, as well as with measures of political legitimacy (inversely) and political conflict.