What is ballot harvesting, and why is Trump tweeting about it during an election-year pandemic?

As many states take steps to encourage voting by mail amid the pandemic, President Donald Trump has frequently falsely linked voting by mail to fraud and criticized the practice of "ballot harvesting."

"Get rid of ballot harvesting, it is rampant with fraud. The USA must have voter I.D., the only way to get an honest count!" he tweeted April 14. 

Ballot harvesting isn’t an official legal term, but it generally refers to someone collecting absentee ballots on behalf of others and then submitting them. Some voting rights experts see the term "ballot harvesting" as pejorative and prefer the term "ballot collection." Many states allow at least certain individuals to collect some ballots on behalf of others.

There have been isolated cases of fraud associated with ballot harvesting, including in a North Carolina congressional race in 2018. But Trump is wrong to suggest that such fraud is rampant. 

Proponents say that the practice helps elderly voters and voters with disabilities, and that it falls under the general category of voter assistance. 

The laws on ballot collection vary nationwide. Current battles over the practice are happening as election officials anticipate big increases in voting by mail because of pandemic fears. 

RELATED: How battleground states are preparing for the pandemic election’s massive increase in voting by mail

The earliest reference in the news we found to the term "ballot harvesting" was related to a 2001 scheme in Yonkers, N.Y., to fix several minor-party primary elections. The term wasn’t used much before 2016, said Amber McReynolds, CEO of Vote at Home and the former director of elections in Denver. 

Ballot harvesting or collection isn’t fraudulent, unless it is done in a way that violates a state law, such as in North Carolina’s 9th Congressional District race  in 2018. Republicans there were criminally charged for illegal ballot collection in order to beat a Democrat. The state ordered a new election after witnesses testified to tampering with absentee ballots. 

Experts have pointed to scattered other examples of illegal ballot collection operations. The conservative Heritage Foundation says it has found 107 cases of fraud linked to absentee ballot collection in its database, which extends back a few decades.

Nine states allow a family member to return a ballot for a voter, according to the National Conference of State Legislatures. Twenty-seven states allow voters to designate someone to return their ballot for them, although some states have placed limits on who can collect the ballots or how many they can collect. Thirteen states are silent on the issue of ballot collection.

In 2016, California expanded the practice with a new law that allowed anyone, including paid workers, to collect and return ballots. Previously, only relatives or people living together could submit ballots for one another. 

Some news reports credited the Democrats’ use of the law with helping them win some 2018 congressional races, while some strategists called that an excuse for Republican losses.

Either way, California Republicans vowed to ramp up their own harvesting operations for the 2020 elections. But the state GOP’s stance changed during the past couple of months amid the pandemic. In April, GOP chair Jessica Millan Patterson sent a letter to Gov. Gavin Newsom stating that ballot harvesting, which may involve strangers visiting voters’ homes, now "presents an intolerable risk to public health and safety." 

Having a person go door to door gathering up mail ballots is ineffective on a mass scale, said University of Florida political scientist Michael McDonald.

"Logistically, voters with ballots in hand are usually not clustered enough to make it practical to do ‘ballot harvesting’ the way Republicans talk about it," he said. 

"While there are always isolated incidents of any type of fraudulent activity in human endeavors, I have never seen a wide-scale attempt to ‘harvest’ ballots against voters’ candidate preferences in a statewide or national election," he said.

RELATED: Amid pandemic, polls show support for voting by mail

Lately, it has been Republicans who have authored bills to limit the number of ballots any individual can collect, said Wendy Underhill, an expert on elections at the National Conference of State Legislatures.

Democratic lawyers and groups, meanwhile, have challenged laws that limit or ban ballot collection. In January, the U.S. Court of Appeals for the 9th Circuit ruled that Arizona’s ban on ballot harvesting violates the Voting Rights Act and disproportionately affects minority voters. The state is appealing the case to the U.S. Supreme Court.

Priorities USA, a Democatic super PAC, filed challenges to ballot collection restrictions in Florida and Pennsylvania and, before the pandemic, in Michigan.

The Republican National Committee has fought efforts to expand ballot collection and defended state laws that limit ballot collection in many battleground states. Republicans are seeking to defend Florida’s current law that bans paid ballot collectors from possessing more than two per cycle in addition to their own ballot. 

The RNC also opposes a bill supported by House Speaker Nancy Pelosi that says states "may not put any limit on how many voted and sealed absentee ballots any designated person can return."

The litigation creates uncertainty about how ballot collections will occur this year.

Voters need multiple secure options to make voting by mail easier, McReynolds said, whether it’s prepaid postage, places to drop off absentee ballots or being able to give your ballot to a trusted friend to drop it off. She pointed to Colorado, which limits collections to 10 ballots, as an example of a safeguard.

"We have to protect voters against bad actors trying to do something like what happened in North Carolina, but it’s a balance," she said. "We have to make sure voters are protected and the system is secure, but also make sure if voters need help they can get it. That’s been my concern about third-party collection. Yes, it can be great, but it can also be bad for voters."