How important is the de facto enforcement of political rights in new democracies? We use the enfranchisement of the emancipated slaves following the American Civil War to study this question. Critical to our strategy, black suffrage was externally enforced by the U.S. Army in ten Southern states during Reconstruction. We employ a triple-difference model to estimate the joint impact of enfranchisement and its enforcement on taxation. We find that occupied counties where black voters comprised larger shares of the electorate levied higher taxes compared to similar non-occupied counties. These counties later experienced greater declines in taxation after the troops were withdrawn. We also demonstrate that in occupied counties, black politicians were more likely to be elected, and political murders by white supremacist groups occurred less frequently. These findings provide evidence on the key role of federal troops in limiting the political capture by Southern elites during Reconstruction.