Donald Trump continues to blame his 2020 election loss on voter fraud. To be clear, there was no widespread fraud or cheating, and Joe Biden won both the Electoral College and popular vote.

You've heard the horror stories: Someone casting multiple ballots, people voting in the name of dead relatives, mail-in ballots being intercepted.

Voter fraud does happen occasionally. When it does, we tend to hear a lot about it. It also gets caught and prosecuted.

The nation's multilayered election processes provide many safeguards that keep voter fraud generally detectable and rare, according to current and former election administrators of both parties.

America's elections are decentralized, with thousands of independent voting jurisdictions. That makes it virtually impossible to pull off a large-scale vote-rigging operation that could tip a presidential race — or most any other race.

"You're probably not going to have a perfect election system," said Republican Trey Grayson, a former Kentucky secretary of state and the advisory board chair of the Secure Elections Project. "But if you're looking for one that you should have confidence in, you should feel good about that here in America."

Election challengers are sworn in before observing the counting of ballots on Election Day on Nov. 3, 2020, at City Hall in Warren, Michigan.

What's stopping people from committing voter fraud?

Voting more than once, tampering with ballots, lying about your residence to vote somewhere else or casting someone else's ballot are crimes that can be punished with hefty fines and prison time. Non-U.S. citizens who break election laws can be deported.

For anyone still motivated to cheat, election systems in the United States are designed with multiple layers of protection and transparency intended to stand in the way.

For in-person voting, most states either require or request that voters provide some sort of ID at the polls. Others require voters to verify who they are in another way, such as stating their name and address, signing a poll book or signing an affidavit.

People who try to vote in the name of a recently deceased friend or family member can be caught when election officials update voter lists with death records and obituaries, said Gail Pellerin, a Democrat in the California Assembly who ran elections in Santa Cruz County for more than 27 years.

Those who try to impersonate someone else run the risk that someone at the polls knows that person or that the person will later try to cast their own ballot, she said.

An election worker sorts mail-in ballots Oct. 26, 2020, at the Miami-Dade County Board of Elections in Doral, Fla. 

What protections exist for absentee voting?

For absentee voting, different states have different ballot verification protocols. All states require a voter's signature. Many states have further precautions, such as having bipartisan teams compare the signature with other signatures on file, requiring the signature to be notarized or requiring a witness to sign.

That means even if a ballot is erroneously sent to someone's past address and the current resident mails it in, there are checks to alert election workers to the foul play.

A growing number of states offer online or text-based ballot tracking tools as an extra layer of protection, allowing voters to see when their ballot has been sent out, returned and counted.

Federal law requires voter list maintenance, and election officials do that through a variety of methods, from checking state and federal databases to collaborating with other states to track voters who have moved.

Ballot drop boxes have security protocols, too, said Tammy Patrick, chief executive officer for programs at the National Association of Election Officials.

She explained the boxes are often designed to stop hands from stealing ballots and are surveilled by camera, bolted to the ground and constructed with fire-retardant chambers, so if someone threw in a lit match, it wouldn't destroy the ballots inside.

A canvasing observer in Allentown, Pa., photographs Lehigh County provisional ballots as counting of votes continues Nov. 6, 2020, three days after the 2020 election. 

Sometimes, alleged voter fraud isn't what it seems

After the 2020 election, social media surged with claims of dead people casting ballots, double voting or destroyed piles of ballots on the side of the road.

Former President Donald Trump promoted and has continued to amplify these claims. But the vast majority of them were found to be untrue.

An Associated Press investigation that explored every potential case of voter fraud in the six battleground states disputed by Trump found fewer than 475 cases out of millions of votes cast. That was not nearly enough to tip the outcome. Democrat Joe Biden won the six states by a combined 311,257 votes.

The review also showed no collusion intended to rig voting. Virtually every case was based on an individual acting alone to cast additional ballots. In one case, a man mistakenly thought he could vote while on parole. In another, a woman was suspected of sending in a ballot for her dead mother.

Former election officials say that even more often, allegations of voter fraud turn out to result from a clerical error or a misunderstanding.

Pellerin said she remembers when a political candidate in her county raised suspicion about many people being registered to vote at the same address. It turned out the voters were nuns who all lived in the same home.

Patrick said that when she worked in elections in Maricopa County, Arizona, mismatched signatures were sometimes explained by a broken arm or a recent stroke. In other cases, an elderly person tried to vote twice because they forgot they had already submitted a mail ballot.

"You really have to think about the intent of the voter," Patrick said. "It isn't always intuitive."

Andrew Hougardy, a worker at King County election headquarters in Renton, Wash., looks at an "alternative format" ballot held up by a co-worker during ballot processing and counting Oct. 23, 2020. 

Why voter fraud is unlikely to affect the presidential race

It would be wrong to suggest that voter fraud never happens.

With millions of votes cast in an election year, it's almost guaranteed there will be a few cases of someone trying to game the system. There also have been more insidious efforts, such as a vote-buying scheme in 2006 in Kentucky.

In that case, Grayson said, voters complained and an investigation ensued. Participants then admitted what they had done.

He said the example shows how important it is for election officials to stay vigilant and constantly improve security in order to help voters feel confident.

However, he said, it would be hard to make any such scheme work on a larger scale. Fraudsters would have to navigate onerous nuances in each county's election system. They also would have to keep a large number of people quiet about a crime that could be caught at any moment by officials or observers.

"This decentralized nature of the elections is itself a deterrent," Grayson said.

A Super Tuesday voter walks past a sign March 5 at a polling location in Mount Holly, N.C.

Explaining Election Day: Understanding the processes from voting to declaring winners

The Associated Press has created a series of videos explaining how elections work in the United States.

Become a #ThisIsTucson member! Your contribution helps our team bring you stories that keep you connected to the community. Become a member today.