I fully expect the Supreme Court to take the Ninth Circuit felon disenfranchisement case out of Washington State if the Ninth Circuit does not do anything with it en banc. (If it does, I could well see the Court applying the doctrine of constitutional avoidance to say that it would not read section 2 to apply to felon disenfranchisement; otherwise Section 2 could be unconstitutional. That would set up an interesting issue for Justice Sotomayor, who faced and rejected such arguments in a case out of New York while on the Second Circuit).
But another case might beat the Ninth Circuit case to the Supreme Court. SCOTUSblog has flagged the petition in Simmons v. Galvin coming out of the First Circuit. (See the cert. petition.)
There is reason to think the Court is likely to take the Ninth Circuit case over the First Circuit case. In the First Circuit case, the appellate court held that section 2 did not give the prisoners a viable claim, a position that a majority of the Court is likely to agree with. In the Ninth Circuit case (assuming no en banc change), the appellate court’s result will give felons the right to vote in Washington state. That seems much more likely to get the Court’s attention.
It is also possible they will take both cases. Or neither.