Voter suppression tactics against African Americans have long existed, yet hard data on their effectiveness was scarce. This article uses unique Louisiana records to fill that gap, analyzing voter registration trends from post-Reconstruction through modern times. Key findings reveal a stark contrast: while state restrictions disproportionately affected Black voters across the period, specific analysis of the 'Understanding Clause' showed an especially sharp decline in Black registration (30pp drop) where it was enforced, with minimal impact on white registrations.

The study demonstrates how historical legal tools created significant disparities despite nominally neutral intent. This work has crucial implications for current debates over voter eligibility laws like ID requirements - which similarly grant officials substantial discretion that can disproportionately affect minority voters.