The purpose of this study is to identify factors influencing the aggregate voter participation rate in the U.S. over the period 1960-2006. Data on all variables is analyzed for even-numbered years only. The percentage of eligible voters who actually voted in each year studied is then considered within a RVM. The explanatory variables include a variable to reflect the impact of unionization of the labor force, the appearance of an all volunteer military, unemployment, the Wars in Iran and Afghanistan, educational attainment, and real disposable personal income. After ADF tests identify non-stationary variables, the empirical estimation reveals that, among other things, the unionization rate of the labor force acted to raise voter participation, whereas the elimination of the military draft reduced voter participation.