CONYERS, Ga. (AP) -- Last November, election officials in a small Rhode Island town were immediately suspicious when results showed 99 percent of voters had turned down a noncontroversial measure about septic systems.
It turned out that an oval on the electronic ballot was misaligned ever so slightly and had thrown off the tally. The measure actually had passed by a comfortable margin.
The scary part: The outcome might never have raised suspicion had the results not been so lopsided.
Amid evidence that Russian hackers may have tried to meddle with last year's presidential election, the incident illustrates a central concern among voting experts — the huge security challenge posed by the nation's 10,000 voting jurisdictions.
While the decentralized nature of U.S. elections is a buffer against large-scale interstate manipulation on a level that could sway a presidential race, it also presents a multitude of opportunities for someone bent on mischief.
With a major election year on the horizon, the Homeland Security Department has been working with states and counties to shore up their election systems against tampering.
States vary widely in what they are doing to tighten security. Colorado and Rhode Island have adopted more rigorous statistical methods for double-checking the votes, while others are making or weighing changes to their voting technology.
"Always, there's been a hypothetical. But clearly, now it is a real threat," said Noah Praetz, election director for Cook County, Illinois. "The fact that we now have to defend against nation-state actors — Russia, China, Iran. It's a very different ballgame now."
Last year, Homeland Security disclosed that 21 states' election systems had been targeted by Russian hackers. There was no evidence they actually penetrated the systems. Experts likened the activity to a burglar jiggling a doorknob to see if it is locked.
In the U.S. — from presidential races down to school board contests — elections are run to a very large degree by local governments, usually counties. County election offices across the nation oversee some 109,000 polling places and more than 694,000 poll workers, and rely on a patchwork of voting technology, such as optical scanners and touchscreens.
Small counties are less likely than the larger and wealthier ones to have cybersecurity expertise and the latest technology.
"The proverb that a chain is only as strong as its weakest link is certainly applicable to our efforts to secure elections," Brian Hancock, director of the testing and certification division for the U.S. Election Assistance Administration, said in a blog on his agency's website.
After the "hanging chad" debacle in Florida threw the 2000 presidential election into confusion, Congress designated $3 billion to help states modernize their election systems.
But those machines are now more than 10 years old. A 2015 study by the Brennan Center for Justice at New York University Law School found that more than 40 states were using machines that were no longer being manufactured, and some election officials had to go onto eBay to find replacement parts, including modems to connect to the Internet.
In September, Virginia banned touchscreen voting machines in next week's closely watched gubernatorial election because of security concerns. Several counties had to scramble to buy replacements.
Georgia, one of five states where voting machines produce no paper trails, is testing out new ones during municipal elections in Conyers, an Atlanta suburb. Voters enter their choices electronically and are then given a paper copy. If the paper looks correct to them, they feed it into a machine that counts their vote.
"This is a wonderful step forward," said James Cabe, a 37-year-old college instructor from Conyers. "I like looking at a piece of paper and verifying that it's the vote I cast."
Georgia officials have estimated it could cost over $100 million to adopt the machines statewide.
In January, Homeland Security designated the nation's election systems "critical infrastructure," on par with the electrical grid and water supply.
A 27-member council has been formed with representatives from federal, state and local governments. The group held its first meeting last month in Atlanta, and a key priority is establishing a process for sharing intelligence.
"It would take a substantial effort to impact our elections, and one that we think is very hard to do," said Bob Kolasky, the acting deputy undersecretary at Homeland Security overseeing the program. "And we are going to make it harder to do."
One step is to provide security clearance to a top election official in each state. So far, 23 states have signed up. The department also has been working with 30 states and 31 local governments to scan their networks for vulnerabilities and provide cybersecurity recommendations.
That's welcome news in places like the Rhode Island town of North Kingstown, population 22,000.
As the polls closed there last fall, Town Clerk Jeannette Alyward checked the state's election night website: Only five people had voted to create a $2 million loan program for septic systems.
Something had to be wrong. By the next day, state officials figured out the ballots weren't being read properly by the machinery because of the bad oval. It was nothing intentional, but it was unsettling — and became more so amid continuing news about Russian hacking.
"I have a lot of confidence in our state system, but could it happen here?" Aylward asked. "Anything could happen."