In many countries, questions about voting rights would be decided against the backdrop of a fundamental constitutional commitment to human dignity. These nations' constitutions protect human dignity, either implicitly or explicitly, not only as an individual right, like due process, but also as a social or civic value that protects people's ability to participate in the process of political decision-making -- picking up on Hannah Arendt's notion that belonging to a political community is an incident of human dignity.
To give just a few examples: The South African Constitutional Court, among others, has used the idea of "civic dignity" to underscore the connection between a person's individual dignity and the democratic foundations of society. In a case involving political engagement beyond just voting at periodic intervals, the Court said: "Participation by the public on a continuous basis provides vitality to the functioning of representative democracy" because, among other things, it "enhances the civic dignity of those who participate by enabling their voices to be heard and taken account of." Doctors for Life International v Speaker of the National Assembly and Others (CCT 12/05)  at 115. In Europe, the German Constitutional Court said that "The right to free and equal participation in public authority is enshrined in human dignity." (Lisbon Case, BVerfG, 2 BvE 2/08, vom 30.6.2009, para. 211 (rejecting a version of the European Constitution because it limited the right of Germans to vote on certain issues which would otherwise be allocated to regional governance). And in a case protecting minority parties, the Peruvian Constitutional Court has said that democracy itself is founded "on the acceptance that the human person and his or her dignity are the beginning and end of the State..." (EXP. No. 0030-2005-PI/TC).
It may not be particularly fruitful to imagine what American constitutionalism would look like if the Supreme Court were to recognize a constitutional commitment to human dignity -- much less the idea that human dignity is the beginning and end of the state. But is it too much to hope that when the Court decides whether Congress has the power to protect the right to participate on an equal basis in electoral politics, it considers how racial discrimination diminishes each person's individual and civic dignity?