WASHINGTON — On its face, the notice sent to 248 county election officials asked only that they do what Congress has ordered: Prune their rolls of voters who have died, moved or lost their eligibility — or face a federal lawsuit.
The notice, delivered in September by a conservative advocacy group, is at the heart of an increasingly bitter argument over the seemingly mundane task of keeping accurate lists of voters — an issue that will be a marquee argument before the Supreme Court in January.
At a time when gaming the rules of elections has become standard political strategy, the task raises a high-stakes question: Is scrubbing ineligible voters from the rolls worth the effort if it means mistakenly bumping legitimate voters as well?
The political ramifications are as close as a history book. Florida’s Legislature ordered the voter rolls scrubbed of dead registrants and ineligible felons before the 2000 presidential election. The resulting purge, based on a broad name-matching exercise, misidentified thousands of legitimate voters as criminals, and prevented at least 1,100 of them — some say thousands more — from casting ballots.
That was the election in which George W. Bush’s 537-vote margin in Florida secured his place in the White House. Controlling the rules of elections — including who is on or off the rolls — has been both a crucial part of political strategy and a legal battleground ever since.
Conservative groups and Republican election officials in some states say the poorly maintained rolls invite fraud and meddling by hackers, sap public confidence in elections and make election workers’ jobs harder. Voting rights advocates and most Democratic election officials, in turn, say that the benefits are mostly imaginary, and that the purges are intended to reduce the number of minority, poor and young voters, who are disproportionately Democrats.
“The goal here is not election integrity,” Stuart Naifeh, the senior counsel at the voting rights group Demos, said. “It’s intimidation and suppression of voters.”
On Wednesday, Demos and two other advocacy groups, the Lawyers’ Committee for Civil Rights Under Law and the Brennan Center for Justiceat the New York University Law School, offered legal help to any of the 248 county election officials who tried to oppose the notice.
The author of the notice to county officials, the Public Interest Legal Foundation, responded quickly. “It seems like we’ve arrived to the point where asking election officials to do what the law requires makes P.I.L.F. subversive,” the group’s president, J. Christian Adams, said in a statement.
Mr. Adams is among several conservatives appointed by President Trump to the White House’s Advisory Commission on Voter Integrity, the voter fraud panel mired in a partisan feud over its operations and political intentions.
The Public Interest Legal Foundation is one of four conservative advocacy groups that have pursued often-overlapping campaigns to purge voter rolls. Three of the groups — the foundation, Judicial Watch and the American Civil Rights Union — rely on former lawyers in the Justice Department’s civil rights division during the George W. Bush administration. The fourth, True the Vote, is an offshoot of a Tea Party group based in Houston.
The groups argue that election officials are ignoring a requirement in the National Voter Registration Act of 1993 that a “reasonable effort” be made to cull ineligible voters — the dead, people who have moved, noncitizens and felons whose voting rights are restricted.
A spokesman for the Public Interest Legal Foundation, Logan Churchwell, said election officials were hobbled by a lack of money and “a failure of imagination.” The law sets few boundaries on tending lists, largely requiring that officials keep voters on the rolls for up to two general elections if they cannot confirm that they have moved. The most explicit prohibitions outlaw striking voters simply because they have not cast ballots and ban delistings within 90 days of elections.
Mr. Churchwell said that too many election officials rely on the mail to determine whether people have moved, depending on voters to return postage-paid confirmation requests sent to their last known address. Voters who lose or fail to return them — or sometimes, never get them — are left on the rolls. The 1993 law, he said, did not anticipate a digital world in which the dead and other ineligible voters can be identified more quickly and perhaps more cheaply.
Example one, he said, is Broward County, Fla., where arguments in a federal lawsuit against the county election supervisor ended this summer. Mr. Churchwell said the foundation discovered three people on the rolls who were alive when Grover Cleveland was president in the 1890s. Election officials “wait for a death certificate to show up and drop in their laps,” he said.
Brenda Snipes, the Broward elections supervisor, said the county followed the same procedures as Florida’s other 66 counties in managing voter rolls. “The court record shows thousands and thousands of people that were purged during the time they expressed concern,” she said.
Broward has a regimen for verifying the status of centenarians, she said, “but you can’t just suspect that a person may be dead or moved away and remove them from the rolls.”
Election officials routinely cull their rolls, but delisting is an exercise fraught with error. Registrants who die in other states — say, New Yorkers who winter in Florida — may pass unnoticed in the states where they are registered.
Officials do tap databases kept by state vital records agencies, the Social Security Administration and the Postal Service, which has a change-of-address list. But the databases cannot assure matches; some jurisdictions do not collect personal information like Social Security or driver’s license numbers that could make a positive ID easier.
And the databases themselves have flaws and anomalies. Voters with similar or identical names compound the odds of accidental delisting. A University of Pennsylvania study of 125 million voter registration files from 2012 found that some three million registrants shared a common first name, last name and date of birth. And registrants from groups where a few surnames are commonly used are especially vulnerable to being mistakenly struck from the rolls.