This is a good question; thanks for asking!

You might be interested in getting in touch with the Landslide Coalition

You might also want to look into other interventions in safeguarding liberal democracy besides voting rights. Hauke Hillebrandt wrote a post attempting to prioritize among these approaches.

Great question! The 80k problem profile for voting reform links to the Center for Election Science and two (1,2) relevant podcast episodes that may connect to the organisations you are interested in.  

Hi BG,

Funny that we were thinking the same thing at the same time. I also want to donate to a voting rights organization, but I'm feeling kind of lost as to how to evaluate them.

If we're looking at the US, my gut is saying to focus on voter turnout rather than voting method (winner take all vs. runoff vs. plurality, etc) because changing our voting method seems like it's a long way off, and my biggest concern about voting rights and elections is that we might fall into a negative feedback loop within the next decade.

At a quick glance, the Brennan Center looks promising in that they're focused on a relatively narrow set of issues, whereas with ACLU or NCAAP a donation could end up going toward a non-voting-related program.

Vote.org (mentioned here https://forum.effectivealtruism.org/s/dmz4gd3hJyrhHgjrM/p/8cr7godn8qN9wjQYj#Elections_and_voting) could also be worth a look.

I'm going to see what information I can find on evaluating political and lobbying organizations in general. I'm hopeful there might be some applicable information out there, even if I can't turn up any analysis on voting rights specifically.