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For about an hour on the night of a primary election in May, residents in Knox County, Tennessee, couldn't tell who was winning.

Hackers had taken down the county's election tracking website, crashing the page at 8 p.m., right as polls were closing. The county's IT director, Dick Moran, said the website had seen "extremely heavy and abnormal network traffic." Its mayor called for an investigation into the cyberattack.

The incident showed all the signs of a distributed denial-of-service attack -- when attackers flood a website's servers with traffic until they can't handle the incoming requests and crash. And it was just the kind of thing that Jigsaw, a tech incubator owned by Google's parent company, Alphabet, wants to prevent. The company is already expecting even more DDoS attacks as Election Day in the US, on Nov. 6, draws closer.

"We have seen that attacks spike in election cycles in different parts of the world," said George Conard, a product manager for Jigsaw's Project Shield.

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On Wednesday, Jigsaw announced that Project Shield, its free DDoS protection tool, would be available to political campaigns, candidates and political action committees. In the past, the tool -- which protects websites from attacks by filtering the flood of traffic -- had been available only for journalists, human rights advocates and, since last March, election monitors and human rights groups.

Jigsaw had seen hackers take down websites for election monitoring in Mexico, France, South Korea and the Netherlands, and hoped to prevent future DDoS attacks. Conard said that political parties, campaigns and organizations are a growing target for cyberattacks during election cycles. And Project Shield won't be just available to major political organizations -- it'll be available to protect local elections as well.

"There are tens of thousands of candidates around the country in local elections, for school boards, city councils," Conard said. "They may not be aware of the threats or have the resources to defend themselves. We want to make sure that everyone is going to be protected, not just the ones with financial resources."

Project Shield currently safeguards about 700 websites from DDoS attacks, Conard said. In 2016, it protected security journalist Brian Krebs' website from attacks powered by the Mirai botnet, which captured more than 600,000 internet-of-things devices and blasted his page with up to 620 Gbps of data.

Cyberattacks against elections have become a national security concern for the US, and potential hackers have multiple tactics available to them to disrupt democracy. The Department of Homeland Security has offered help to state election officials to make sure their voting machines are hack-proof and make sure campaign officials know how to keep themselves safe.

The focus comes as the US heads into midterm elections and many Americans are worried about Russian interference happening again, as it did in 2016.

Massive DDoS attacks, some of which can cost up to $200,000 a year to fend off, can be bought, often for just $20 online. It's all set up so that anyone wanting to shut down a website could, without needing the technical expertise of a skilled hacker.

Conard said he's seen even lower prices online for DDoS attacks.

"You can imagine a scenario where someone -- it doesn't have to be a super sophisticated organization -- that doesn't like the point of view that a candidate represents, and quickly finding a site that can launch an attack for as low as $4," he said.

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