The potential implications of Shelby County may be massive for Indian voting. I’m no expert, but eyeballing the covered jurisdictions (or should I say formerly covered jurisdictions), I see a lot of Indian country.
I see Alaska and Arizona, but thousands upon thousands of Indian voters potentially affected. I see Shannon and Todd Counties in South Dakota. Obviously Lakota territory. I even see Allegan County in Michigan, where the Gun Lake Tribe is located. [Wrong township.] There’s Robeson County in North Carolina where the Lumbees are, and Kings County in California.
Turtle Talk 
When Congress was considering reauthorization of the VRA in 2006, reports were written about how the VRA has operated in certain states (including South Dakota and Alaska). Worth a read, the decision yesterday will definitely have big impacts for tribal citizens. http://www.civilrights.org/voting-rights/vra/states.html
Including the three federally recognized tribes in Texas.