The voting disputes that have burst onto the national scene are just the biggest lightning bolts in a storm that has been brewing over registered-voter rolls for more than a year.
In some of the battleground states where President Trump is challenging the vote count favoring presumptive President-elect Joseph R. Biden, lawsuits over dirty voter rolls and the potential for abuse already were winding through the courts.
A lawsuit has been pending since April in federal court in Pennsylvania, where Mr. Biden overcame a nearly 1.3 million vote deficit on Election Day.
In Georgia, where after days of counting Mr. Biden appears poised to be the first Democrat to win its presidential vote since 1992, a lawsuit claiming voting-roll improprieties in Fulton County has been working its way through the courts since July.
“I never thought it would wind up having anything to do with the presidential race,” Georgia attorney Ray Smith III said. “But this has been an issue for years.”
Mr. Smith, a Republican, once served on the Fulton County Board of Registration and Elections. He is now a part of Mr. Trump’s recount team.
In his complaint against the Georgia secretary of state and the Fulton County Election Board, Mr. Smith alleges that more than 15,000 voters on the rolls no longer live there and that at least 1,200 are also registered outside of Georgia.
Georgia’s Republican Sens. David Perdue and Kelly Loeffler, both of whom face Jan. 5 runoff elections for their seats, have called on Secretary of State Brad Raffensperger to resign. He rejected the call.
Mr. Smith’s lawsuit on behalf of two voters was primarily directed at Georgia legislative elections but took on new meaning with the national election. The day before Election Day he sent a letter to the secretary of state and county officials reminding them of his clients’ complaint.
Mr. Raffensperger and other officials have said there are no examples of voting fraud or irregularities that would call the vote count into question. Mr. Biden’s lead in Georgia is around 14,000 votes and a hand recount has been authorized.
Georgia is not an outlier.
In April, the conservative watchdog group Judicial Watch filed lawsuits in Pennsylvania, North Carolina and Colorado accusing officials of failing to enforce provisions of the 1993 National Voter Registration Act, chiefly by failing to check millions of people on the rolls who had not voted for years.
“It’s a major issue that the rolls are dirty, because dirty rolls lead to dirty elections,” said Tom Fitton, Judicial Watch president. “The rolls are filthy.”
The suspect numbers in Pennsylvania are even bigger than Georgia’s. The conservative group’s suit contends more than 800,000 names should be purged.
Pennsylvania figures show Mr. Trump’s Election Day lead of more than 1.25 million votes was overtaken by Mr. Biden’s nearly 4-to-1 advantage in mail-in ballots. Mr. Biden currently leads 49.8% to 48.1% with nearly 6.7 million total votes tallied.
Judicial Watch singled out three counties around Philadelphia — Bucks, Chester and Delaware — that, like the city, are Democratic strongholds. In those counties, state figures show between 83% and 87% of 444,000 mail-in ballots were returned.
The lawsuit was put in limbo before the election by U.S. District Judge Christopher Conner, a George W. Bush appointee, who based his continuation in part on the chaotic election conditions imposed by the COVID-19 pandemic.
Mr. Fitton stressed he is not saying that all the names Judicial Watch thinks should be stricken from the rolls actually voted.
The legal efforts concerning the NRVA are led by Robert Popper, an attorney who spent 12 years with the Department of Justice but grew frustrated by its unwillingness to enforce parts of the law.
During the eight years of the Obama administration, not a single case was launched, and earlier former Attorney General Janet Reno had given Los Angeles County an effective waiver against enforcing NRVA provisions, Mr. Popper said.
“There is a level of indifference to it that is ideological,” he said. “It seems a strange matter of principle to say ‘let’s not enforce it.’”
Last year, Los Angeles County reached a settlement in which it agreed to strike 1.6 million inactive voters. Kentucky entered into a consent decree to more aggressively police voter registration rolls after the Justice Department intervened in that suit.
“It’s disturbing so many state and local officials continue to resist,” Mr. Fitton said. “We’re not asking for a lot.”