In this paper we examine the impact of electoral laws on overall turnout, and class bias in the electorate. We look at the impact of changes in registration laws on who votes, with particular attention to the discriminatory impact of legal changes on persons at different segments of the income distribution. By aggregating turnout for different demographic groups – persons with different levels of education and income – by state, and then pooling those state level turnout rates over time, we can use cross sectional time series analysis to estimate the impact of electoral reforms. This gives us much more powerful estimates of these effects than were previously available. We do not suffer from the problems of cross-sectional analyses which rely on the assumption that the choice of electoral regime is independent of the likelihood of voting. And by using all presidential elections from 1972 thru 2004 we have much more statistical power than has been provided by previous analyses simply looking at difference of means tests across two elections. We consider the impact of: the number of days prior to election day that registration closes; the availability of election day registration; the availability of early voting, and the availability of absentee voting.