Last week, during a world-renowned law enforcement conference in Boston, two FBI agents briefed dozens of police chiefs and sheriffs on the wide array of threats to government officials, poll workers, candidates and voters that the FBI has been seeing in the days before next week's presidential election.

The closed-door briefing, described to ABC News, lasted nearly an hour, highlighting not only physical threats tied to the election but also efforts by Russia and other foreign adversaries to convince Americans that the election results can't be trusted.

When the FBI officials finished their briefing at the International Association of Chiefs of Police conference, there was only one question from the audience: What do the agents have to say about "2,000 Mules," a two-year-old documentary that claims to expose widespread voter fraud in the 2020 election?

The film has been widely debunked, and its distributor went so far as to remove it from its platforms earlier this year.

In response to the audience member's question, the agents said they hadn't seen the film and couldn't comment on it if they had.

Still, the exchange reflects how conspiracy theories about elections -- and the FBI's alleged efforts to tip their outcomes -- have become so embedded in parts of America that even some law enforcement officials wonder about them -- even after they've been refuted.

Current and former FBI officials say that the penetration of false narratives has put the FBI in the tough position of trying to defend election officials and voters against myriad threats, while also having to defend the FBI itself in ways it's never had to before.

"It speaks to just the volume of conspiracy theories ... [and] the divisiveness that we're seeing across the country that the FBI has to navigate," said Eric Miller, who as a supervisory special agent in the FBI's Washington, D.C., field office until 2021, oversaw a squad that investigated election crimes and public corruption.

The FBI told ABC News in a statement that its mission is "to protect the American people and uphold the Constitution," and that its people work "every day to fulfill these promises without fear or favor."

'A different environment'

As with every election, the FBI is expected to investigate election-related threats, allegations of ballot fraud, suspected foreign interference, and other reported attempts to disrupt the election process.

"In keeping with our standard Election Day protocol, FBI headquarters will stand up a National Election Command Post to provide a centralized location for assessing election-related threats ... [and to] track status reports and significant complaints from FBI field offices," the FBI said in its statement to ABC News.

But while the bureau's responsibilities will be the same as always, some feel this year's election presents an unprecedented challenge.

"This is a different environment than we've ever had to deal with," a former senior FBI official who was involved in the FBI's election-related operations in 2016 and 2020 told ABC News.

As voters head to the polls, they're casting their ballots nearly four years after a violent mob stormed the U.S. Capitol in an effort to stop Congress from certifying the last presidential election. Just four months ago, a Pennsylvania man nearly assassinated former President Donald Trump at a campaign rally, and three weeks ago the FBI arrested an Afghan immigrant in Oklahoma for plotting an Election Day terrorist attack on behalf of ISIS.

Federal authorities also continue to warn that other "threat actors" are "likely to leverage claims of election fraud" to foment election-related violence, as a Department of Homeland Security assessment put it earlier this week. According to officials, Iran is determined to assassinate Trump and some of his former top advisers, Russia won't back down in its malicious campaign to sow chaos and influence the election, and China is trying to hack the phones of both political parties.

'A challenging spot'

Meanwhile, the FBI has itself been accused by Trump and his allies of trying to influence the election, through its investigations of Trump, its search of his Mar-a-Lago estate, and the Justice Department's handling of cases tied to President Joe Biden and his son Hunter.

"It's called election interference. It's called the weaponization of the FBI," Trump said at a campaign event in Georgia last week. The former president has reportedly vowed to fire FBI Director Chris Wray if he wins reelection -- even though it was Trump himself who picked Wray to lead the bureau in 2017.

The FBI has strongly disputed that it's influenced by politics in any way.

"[W]e remain firmly committed to carrying out our mission while protecting the civil liberties of the citizens we serve," the FBI said in its statement to ABC News.

The politically-charged atmosphere has led the FBI to become a target of violence. In 2022, after the FBI searched Mar-a-Lago, an Ohio man reportedly issued an online "call to arms" and then opened fire at the FBI's field office in Cincinnati.

Several months later, authorities arrested two Tennessee men for allegedly plotting attacks on FBI agents in Knoxville. And earlier this year, a South Carolina man who reportedly espoused right-wing conspiracy theories rammed his vehicle into a gate at the FBI's office in Atlanta.

The FBI is in "an awkward, challenging spot," the former senior FBI official said.

'24/7 command post'

According to FBI officials, the bureau has spent months "engaged in extensive preparations" for Election Day.

"As always, we are working closely with our federal, state, and local partners so everyone involved with safeguarding the election has the information and resources necessary to respond in a timely manner to any criminal violations that may arise," the FBI said in its statement.

FBI headquarters is planning to keep its National Election Command Post operational until at least Nov. 10, reflecting how authorities are concerned about what might happen even after the polls close on Nov. 5. The command post will include senior officials from the FBI's counterterrorism, criminal, counterintelligence and cyber divisions.

And FBI leadership has told each of the agency's 55 field offices to set up their own form of a "24/7 command post" -- though what that actually looks like in each case will vary depending on the office's size and location, and any developments in the field, ABC News was told.

"Some of it is a 'command post' in the sense of making sure if something happens, we have the requisite people there," including lawyers and leaders who can make quick decisions, the former FBI official explained. "It's not [necessarily] like a command post you see on TV with 20 people in a room monitoring the TVs and the security cameras."

As described to ABC News, the FBI field offices will be prepared to receive any reports of threats or criminal conduct from state or local officials, including election boards and law enforcement agencies. The field offices will then triage the reports and send them to the command post at FBI headquarters, where the information will be cross-referenced with classified intelligence and information coming in from other field offices.

"The Phoenix field division is not going to know what is going on in Chicago at the same time," Miller said, so "that allows the FBI to see patterns of threat activity" and determine if something bigger might be unfolding across the country.

The command post would then "provide guidance to FBI field offices" and "coordinate any FBI response to any election-related incident," the FBI said in its statement.

Based on the current environment, "we expect our federal law enforcement agencies to be on standby for an election that years ago would be no problem whatsoever," the former FBI official said.

"You hope someday the bureau doesn't need to do a command post," he said. "Maybe that day will come -- but that day is not now."