Trevor Hughes

USA TODAY

DENVER — Elections officials across the country are bracing for a deluge of eager but inexperienced poll watchers by training on how to handle conflict and confrontation and even preparing for mass shootings when voters cast ballots Nov. 8.

Republican nominee Donald Trump's unprecedented criticism of a “rigged" election process and his refusal to say he'll concede if he loses have elections officials preparing for a contentious day. Trump has called on his supporters to monitor election sites — even signing up volunteers on his campaign website — but he hasn’t specified what kind of fraud he believes will happen at the polls.

The USA TODAY Network interviewed dozens of Trump supporters across the USA but found little evidence of a coordinated poll-watching effort. Still, social media are rife with assertions from Trump supporters that they’ll flood polls to watch for fraud, possibly wearing red shirts. They've called for an “activation” by law enforcement and Trump supporters on Election Day.

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Online, his supporters discuss rumors of the dead casting ballots, including some cases under investigation in Colorado, and suggest they’ll monitor polls for people who “don’t speak American.”

Kristen Clarke, president and executive director of the Lawyers’ Committee for Civil Rights Under Law, said her organization fears unsanctioned poll watchers targeting voters based on their language or apparent ethnicity.

Federal law requires that voting materials be printed in alternate languages if enough people in that area don’t speak English fluently, because speaking English isn't a legal voting requirement. Among the alternate languages: Inupiat, Cherokee and Choctaw, languages spoken by Native American tribes.

“There is cause for concern. We’re already seeing and feeling the impact,” Clarke said. “We are deeply concerned about the intimidating effect these statements might have on voters.”

Election "rigging" claims reached new heights during the final presidential debate Wednesday night, when Trump declined to say whether he would accept the election results. (Thursday, he said he’d accept them if he won.)

"I will look at it at the time," Trump replied, citing the "corrupt media." He claimed — without specific evidence — that millions of people are registered to vote who shouldn't be.

Elections are generally monitored by multiple groups, from officially sanctioned and party-organized poll watchers with special training to lawyers working on behalf of the candidates. Clinton’s campaign has been recruiting via Facebook for attorneys and law students to watch polls.

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Florida Republican Party State Committeeman Chris Crowley, 49, said the Lee County GOP will have volunteer poll watchers. He said online calls for an uprising were overblown.

“Nobody I know has said anything about a revolution,” said Crowley, a Fort Myers lawyer. “But I guess it depends on how many dead people vote.”

Officials said they’re confident the party- or campaign-sanctioned watchers will follow the rules, which generally prohibit direct confrontations of voters within polling locations. What they’re worried about are untrained but enthusiastic members of the public who don’t understand the specific rules governing elections. Those kinds of monitors, said Arapahoe County (Colo.) Clerk and Recorder Matt Crane, are “unhelpful.”

Crane has trained his staff to deal with a potential mass shooting, political conflicts and even how to handle campaigns handing out free pizza to voters waiting in line. He said every presidential election draws heightened attention to voting access, and his staff spent more time preparing for this election than any of the four previous ones he’s worked.

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“I haven’t seen anything out of the norm yet, and, knock on wood, we won’t see anything out of the norm,” he said. “If somebody wants to vote, we want to make sure the process is as open as possible while maintaining the integrity of the election.”

The unusual attention to voting prompted Pennsylvania officials to remind poll workers that voters are permitted to carry firearms while voting in most parts of the state, except for schools and courthouses.

The state bars anyone from the “ostentatious showing” of a firearm at a polling location, which it considers potential voter intimidation. Trump singled out Philadelphia as a place where he has concerns, and the state’s Republican Party recruited more poll watchers than in previous years, said Megan Sweeney, a Pennsylvania Republican Party spokeswoman.

In Michigan, Republican Party officials were ahead of their usual recruiting goals for poll watchers, and they hope to cover more than 700 precincts with party-affiliated watchers. Those watchers are instructed not to engage with voters and instead just make sure they either produce valid identification or sign affidavits of identify. Michigan has more than 4,800 precincts.

In Colorado, which Trump has repeatedly visited because he considers it critical to a victory, Crane said he welcomes calls for transparency in the elections process. He said the best way to ensure transparency is for concerned citizens to undergo party-sponsored poll-watcher training. In some cases, that training includes required certification for viewing and handling personal information, such as home addresses and signatures.

“We welcome that check,” said Crane, a Republican. “The only thing we ask is that you go through the party to get trained up.”

Contributing: Kathleen Gray, Detroit Free Press; Arek Sarkissian, Naples Daily News​​; Brett Sholtis, York Daily Record.

Elections 2016 | USA TODAY Network