Ohio's elections chief said Wednesday that more than 275,000 inactive Ohio voters are about to get their final opportunity to keep from dropping off the rolls.

Republican Secretary of State Jon Husted said that's the total number of so-called "last chance mailings" going out from county boards of elections as part of Ohio's contested process for keeping its list of eligible voters up-to-date.

Ohio's procedure for maintaining its voter rolls is considered one of the most stringent in the nation, because it employs a "supplemental process" that has led to the removal of thousands of people who failed to vote and then didn't respond to government requests to affirm their registrations.

Civil rights groups unsuccessfully challenged Ohio's regimen as a voter "purge" ahead of last year's election — claiming it violated a provision of the voter registration law that prohibits rescinding someone's registration "by reason of the person's failure to vote."

The U.S. Supreme Court rejected their arguments, finding in Husted's favor. Nonetheless, he temporarily put the procedures on hold to avoid confusion during the November election, in which he was elected lieutenant governor.

Husted characterized last chance mailings as part of his office's efforts to help voters stay registered — not to kick them off the rolls. Those efforts also include new online notifications for voters about changes to their registration status and the use of Bureau of Motor Vehicles data to confirm a voter's address.

"From online voter registration to these last chance mailings, every innovative reform implemented by my office over the last eight years has been done to make it easier to vote and harder to cheat," he said in a statement. "We want every eligible Ohioan to be an engaged, active participant in our elections."

Spokesman Matt McClellan said those who respond properly to the last chance mailings will remain registered. And if they drop off, he said, they can easily re-register online.

Husted's successor, Republican Frank LaRose, previously expressed interest in changing the purge process.

Ohio's voting rules are of particular interest nationally, because it's one of the larger swing states with the potential to determine the outcome of presidential elections.

The state's maintenance procedures stemmed from a requirement in federal law that states have to make an effort to keep their voter rolls in good shape by removing people who have moved or died. Husted's office said most of the 275,000 voters receiving last chance notices have, in fact, probably either moved out of state or died.

Ohio secretaries of state of both parties have used voters' inactivity to trigger the removal process since 1994.