Washington (CNN) The Supreme Court on Tuesday agreed to hear a case concerning whether Ohio's method of removing names from its voter rolls violates federal law.

A federal appeals court said last fall that the program violated the National Voter Registration Act, and the state of Ohio appealed.

The appeals court said that Ohio's so-called "supplemental process," where "a voter is purged from the rolls after six years of inactivity -- even if he or she did not move and otherwise remains eligible to vote," is in violation of the voter law.

The ruling was a victory for the American Civil Liberties Union of Ohio and other groups who expressed concern that the purge would impact "many thousands" of Ohio voters.

Ohio's Secretary of State Jon Husted defended the state's process. In court papers filed with the Supreme Court, he noted that the voters who have not engaged in voter activity for two years are sent notices. If a voter returns the notice through prepaid mail or responds through the internet, his information is updated. If the notice is ignored and the voter fails to update a registration over the next four years, the registration is canceled.

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