The Florida Legislature last week created a law enforcement agency — informally called the election police — to tackle what Gov. Ron DeSantis and other Republicans have declared an urgent problem: the roughly 0.000677 percent of voters suspected of committing voter fraud.

In Georgia, Republicans in the House passed a law on Tuesday handing new powers to police personnel who investigate allegations of election-related crimes.

And in Texas, the Republican attorney general already has created an “election integrity unit” charged solely with investigating illegal voting.

Voter fraud is exceedingly rare — and often accidental. Still, ambitious Republicans across the country are making a show of cracking down on voter crime this election year. Legislators in several states have moved to reorganize and rebrand law enforcement agencies while stiffening penalties for voting-related crimes. Republican district attorneys and state attorneys general are promoting their aggressive prosecutions, in some cases making felony cases out of situations that in the past might have been classified as honest mistakes.

It is a new phase of the Republican campaign to tighten voting laws that started after former President Donald J. Trump began making false claims of fraud following the 2020 election. The effort, which resulted in a wave of new state laws last year, has now shifted to courthouses, raising concern among voting rights activists that fear of prosecution could keep some voters from casting ballots.

“As myths about widespread voter fraud become central to political campaigns and discourse, we’re seeing more of the high-profile attempts to make examples of individuals,” said Wendy Weiser, the vice president for democracy at the Brennan Center.

It’s nearly impossible to assess whether the talk of getting tough on voter crime is resulting in an increase in prosecutions. There is no nationwide data on how many people were charged with voter fraud in 2020 or in previous elections, and state data is often incomplete. The state numbers that are available show there were very few examples of potential cases in 2020 and few prosecutions.

Florida election officials made just 75 referrals to law enforcement agencies regarding potential fraud during the 2020 election, out of more than 11 million votes cast, according to data from the Florida secretary of state’s office. Of those investigations, only four cases have been prosecuted as voter fraud in the state from the 2020 election.

In Texas, where Attorney General Ken Paxton announced his new “election integrity unit” in October to investigate election crimes, The Houston Chronicle reported that the six-prosecutor unit had spent $2.2 million and had closed three cases.

And in Wisconsin, where a swath of Republicans, including one candidate for governor, are seeking to decertify the state’s 2020 presidential election results on the basis of false claims of fraud, a report released last week by the Wisconsin Election Commission said that the state had referred to local prosecutors 95 instances of felons’ voting in 2020 when they were not allowed to. From among those cases, district attorneys have filed charges against 16 people.

“The underlying level of actual criminality, I don’t think that’s changed at all,” said Lorraine Minnite, a Rutgers University political science professor who has collected years of data on election fraud in America. “In an election of 130 million or 140 million people, it’s close to zero. The truth is not a priority; what is a priority is the political use of this issue.”

The political incentives to draw attention to the enforcement of voting laws are clear. A Monmouth University poll in January found that 62 percent of Republicans and just 19 percent of Democrats believed voter fraud was a major problem.

That may mean the odds of being charged with voter fraud can be linked to the political affiliation of the local prosecutor.

In Fond du Lac County, Wis., District Attorney Eric Toney was in office for nine years without prosecuting a voter fraud case. But after he started his campaign for attorney general in 2021, Mr. Toney, a Republican, received a letter from a Wisconsin man who had acquired copies of millions of ballots in an attempt to conduct his own review of the 2020 election. The letter cited five Fond du Lac County voters whose registrations listed their home addresses at a UPS Store, a violation of a state law that requires voters to register where they live.

Mr. Toney charged all five with felony voter fraud.

“We get tips from community members of people breaking the law through the year, and we take them seriously, especially if it’s an election law violation,” Mr. Toney said in an interview. “Law enforcement takes it seriously. I take it seriously as a district attorney.”

One of the voters charged, Jamie Wells, told investigators that the UPS Store was her “home base.” She said she lived in a mobile home and split time between a nearby campground and Louisiana. Ms. Wells did not respond to phone or email messages. If convicted, she stands to serve up to three and a half years in prison — though she would most likely receive a much shorter sentence.

In La Crosse County, Wis., District Attorney Tim Gruenke, a Democrat, received a similar referral: 23 people registered to vote with addresses from a local UPS Store, and 16 of them voted in 2020. But Mr. Gruenke said he had concluded that there was no attempt at fraud. Instead of felony charges, the local clerk sent the voters a letter giving them 30 days to change their registrations to an address where they lived.

“It didn’t seem to me there was any attempt to defraud,” Mr. Gruenke said. “It would be a felony charge, and I thought that would be too heavy for what amounted to a typo or clerical error.”

Mr. Toney linked his decision to his views about the 2020 election in Wisconsin, which the Democratic candidate, Joseph R. Biden Jr., won by more than 20,682 votes out of 3.3 million cast.

While he had never challenged Mr. Biden’s win, he said he believed that “there is no dispute that Wisconsin election laws weren’t followed and fraud occurred.”

“I support identifying any fraud or election laws not followed to ensure it never happens again, because elections are the cornerstone of our democracy,” Mr. Toney said.

(Ms. Wells, one of the voters Mr. Toney has charged, also said she believed something was amiss in the 2020 election. “They took it away from Trump,” she told investigators.)

Mr. DeSantis in Florida is perhaps the best-known politician who is promoting efforts to bolster criminal enforcement of voting-related laws. The governor, who is up for re-election in November, made the new police agency a top legislative priority. .

The unit, called the Office of Election Crimes and Security, takes on work already done by the secretary of state’s office, but reports directly to the governor.

“Florida is going to be on the cutting edge of this,” said Jessica Anderson, the executive director of Heritage Action, a conservative advocacy group that supports the bill.

Mr. DeSantis isn’t alone. In Arizona, State Senator Wendy Rodgers, a Republican who is trying to overturn the 2020 election, is sponsoring a bill that would establish an “election bureau” to investigate fraud with sweeping authority, including the ability to impound election equipment and records.

In Georgia, Republicans in the House passed a voting bill on Tuesday that would, among other changes, expand the authority of the Georgia Bureau of Investigation to identify and investigate election violations, including the ability to conduct election audits of any subpoenaed documents.

Republican efforts also extend to election administrators. Republicans in Texas last year increased the penalties on election workers who are accused of influencing a voter’s decision while offering assistance, such as translations.

But Florida’s legislation would be the first in the nation restricting how election officials can defend themselves in court. The bill bars them from accepting legal defense provided or funded by a nongovernmental agency.

That provision has drawn bipartisan criticism. “The principle that a state would deny legal representation of an election official’s choice when they’re being pursued for criminal charges is profoundly against the rule of law,” said Ben Ginsberg, a lawyer for Republican presidential campaigns and national committees before breaking with the party during the Trump era.

Mr. Ginsburg and Bob Bauer, a prominent Democratic lawyer, have started the Election Official Legal Defense Network, an organization of lawyers that gives free legal advice and representation to election administrators.

Sentences for those convicted of voter fraud vary widely. A Minnesota man who was on probation for a felony was ordered to pay a $214 fine this week after pleading guilty to lying about his voting eligibility on an absentee ballot application. He never returned the ballot.

But in Memphis, Pamela Moses was sentenced to six years in prison in January after registering to vote when she had a felony conviction. The voter fraud conviction was thrown out last month and a new trial ordered when a judge ruled that the Tennessee Department of Corrections had improperly withheld evidence that was later uncovered by The Guardian.

In a statement, the Shelby County district attorney, Amy Weirich, a Republican who faces re-election this year, blamed Ms. Moses for the long sentence. “I gave her a chance to plead to a misdemeanor with no prison time,” Ms. Weirich said. A spokesman said Ms. Weirich hadn’t decided whether to pursue a new trial.

Ms. Moses, a musician and Black Lives Matter activist, said she hadn’t known she was ineligible to vote.

“They did make an example out of me,” she said in an interview. “They showed every Black person in Tennessee and whoever else saw this case, you better not vote, they’re going to put you in jail.”

Kitty Bennett contributed research.