This study examines the dynamics of electoral reforms in the constituent entities of the Russian Federation and their influence on the disproportionality of parliamentary representation since the electoral system experienced major changes in 2003. We suggest that some characteristics of the electoral system may be highly instrumental in ensuring and maintaining United Russia’s influence in legislative bodies. This makes it possible to classify them as forms of institutional manipulation typical of electoral authoritarianism. Based on the statistical description and regression analysis, the study demonstrates the impact of some elements of electoral reforms on disproportionality during the periods at issue. At the same time, we can identify the methods of cementing the dominant party’s hold on power that the authorities find the most effective. In this regard, we make the conclusion that certain elements of the electoral system function as a balanced mechanism, which is evidenced by how they have been used during the different periods. Additionally, the study analyses the impact of disproportionality on electoral behavior, with the hypothesis about its negative influence on the electoral turnout being supported. Yet we regard the lower turnout as a consequence of the voting behavior of both the opposition’s supporters and loyalists. Finally, the electoral reforms in Russia seem to have put limits on disproportionality of parliamentary representation due to the issue of legitimacy.