HOUSTON -- They go by names like Oath Keepers, Wolverine Watchmen and the Three Percenters. They chat on Gab, Discord, 4chan and other social media. Heavily armed and loyal to President Donald Trump, many vow to descend on polling places Nov. 3 in a far-right show of unity.

Armed, far-right groups have long echoed at the fringes of American politics, drawing white nationalists and other extremists to their ranks. But over the last four years -- when conservative causes have collided with social justice movements -- their voices have grown louder, their actions more brazen. The alleged plot this past week by extremists to kidnap Michigan Gov. Gretchen Whitmer was a stunning indication of the potential for domestic terrorism.

The groups are now turning their attention to battleground states in the most consequential election in generations. Far-right organizations have rallied around Trump, positioning themselves as a counterforce to movements like the antifascist antifa and Black Lives Matter, whom they blame for nationwide protests that have stirred unrest in recent months. The majority of Black Lives Matter protesters have been nonviolent.

The Oath Keepers claim thousands of members, including those who served in the military and law enforcement. Some have signed up as poll watchers, while others plan to monitor the election armed and "undercover," drawing their weapons if needed, said founder Stewart Rhodes, a former Army paratrooper and Yale law school graduate: "We'll be out on Election Day to protect people who are voting."

With political tensions running high across the country, protesters from a variety of groups could clash at polling places and protest sites. That happened Saturday in Denver when a man was shot and killed in a skirmish between far-left and far-right activists. Experts are especially focused on dangers raised by armed right-wing factions and self-styled militias with national networks who may intimidate voters, particularly immigrants and people of color.

"The chances are really high that we're going to see militia members, armed groups or Trump supporters who are armed at the polls," said Cassie Miller, a senior researcher with the Southern Poverty Law Center. "Not only are these people willing to participate in voter intimidation, but they're hoping to create this chaotic moment. There's an unwillingness to accept anything but a Trump victory."

The groups fall under the far-right banner but they're not uniform in their methods and beliefs. Most express support for law enforcement, but have vigilante tendencies. Some call themselves law-abiding militias. Others, like the Oath Keepers, reject militia, white supremacist and racist labels. Those like the Proud Boys, which has been designated a hate group, and the Boogaloo movement, another far-right antigovernment group, are prone to violence and see the election as an opportunity.

They have become increasingly vocal in politics. But the threat of extremists has a deep history, including the 1995 Oklahoma City bombing by antigovernment terrorist Timothy McVeigh, which killed 168 people at the Alfred P. Murrah Federal Building, and the 2016 standoff in Oregon between supporters of Nevada cattle rancher Cliven Bundy and federal authorities.

Trump's rhetoric over the last four years has been regarded by far-right organizations as implicit endorsement. In 2017, when neo-Nazis and white supremacists at the "Unite the Right" rally attacked peaceful demonstrators in Charlottesville, Va., killing a protester, the president did not immediately condemn them. Last month, during his debate with Joe Biden, Trump told the Proud Boys to "stand back and stand by" before saying the next day that he was not aware of the group.

Many armed groups have been banned from mainstream social media platforms such as Facebook, which this past week also purged QAnon conspiracy theorists, who believe Satan-worshiping pedophiles are running a global child sex-trafficking ring and plotting against Trump. But armed groups' online chatter about the election has not been muffled: They rely instead on private Telegram channels, member-only forums and the Zello walkie-talkie app.

A post to a QAnon-affiliated Telegram group with 5,200 subscribers this month warned of "heavily armed MAGA patriots" standing ready for the election, according to SITE Intelligence Group, a Bethesda, Md.-based research organization that tracks extremists online.

"I want nothing more than to stand down and live in peace, but if it goes bad, God forgive me for what I do when they force my hand," an Oath Keeper wrote while discussing the election on a members-only forum this month. "It's not going to end, these people, and I hate saying it, are going to have to be stopped. Is President Trump going to, with the aid of the proper authorities, arrest them or are we the people going to have to get involved?"

In another online forum of Three Percenters -- an armed group that draws its name from the supposed 3% of colonists who fought the American Revolution -- a Vermont member warned, "November is almost here, prepare for anything! Reach out to your neighboring states and work on those relationships to increase your intel as well as regional strength."

People showing up armed at protests have led to several deaths this year. Kyle Rittenhouse, a 17-year-old vigilante now celebrated by some right-wing groups, was charged in August with homicide in connection with the fatal shooting of two people in Kenosha, Wis., during protests against a police shooting of a Black man. Last month, a supporter of the right-wing Patriot Prayer was fatally shot in Portland, Ore., by an antifa-affiliated protester later killed by federal agents attempting to arrest him.

Michigan militia members had rallied at -- and inside -- the state Capitol this year to oppose the state's COVID-19 restrictions. But concern over violence increased this week after state and federal authorities there charged 13 men with plotting to kidnap the Democratic governor and put her on trial for "uncontrolled power." In recent weeks, the men had trained and dubbed themselves the Wolverine Watchmen.

Adam Peisker, an officer with the Michigan Home Guard, one of the largest militias in the state with more than 300 members, condemned the men charged this past week, saying he knew one who "has a past of not fitting in well and being kicked out of militias." He said the Wolverine Watchmen were not a known militia, but that it's common for militias to form in Michigan, then dissolve or merge with national groups.

Peisker, 32, a firefighter in southeast Michigan, said his group would not be poll watching but, "If rioting happens, we will have to assess where are the damages. We protect our members first, then we reach out to law enforcement and see where we can help."

The Department of Homeland Security warned this past week that antigovernment groups could carry out attacks over a perceived "infringement of liberties and government overreach" with polling sites "likely flash points for potential violence."

A report by the Giffords Law Center to Prevent Gun Violence predicted: "It is likely that significant numbers of people will bring guns to polling places under the guise of preventing election fraud."

Georgetown Law School created an online tool to check laws concerning guns at polling places.

Twenty-five states, including California, have statutes that criminalize certain paramilitary activity, according to a Georgetown Law report.

Black Lives Matter protesters in swing states also plan to go to the polls to protect voters from being intimidated by right-wing groups: "This could be the biggest voter turnout in history, a lot of them people of color," said KeJuan Goldsmith, 19, a Black activist college student who led a protest against police brutality in Green Bay, Wis., on Saturday. "If we need to be there for them to be protected, so they can cast their vote without fear, that's what we have to do."

Rhodes, 55, said the Oath Keepers militia plans to proactively monitor polling places as it did during the last presidential election, reporting problems to police. He said it's most concerned with swing states such as Minnesota, North Carolina and Wisconsin and has intelligence analysts looking at other states where the vote's expected to be close.

Rhodes, a former criminal defense lawyer, tells members of his group to obey the law and not to menace voters. His group has provided volunteer security at recent Trump rallies, where he claimed supporters were attacked by armed counterprotesters. He fears they will show up at the polls, where Trump supporters, many of whom tend to be skeptical about the dangers of COVID-19, are more likely to vote in person.

"I'll be voting in person and so will everybody else I know, and I think the radical left knows that," Rhodes said by phone while visiting Houston this week. He supports law enforcement, but said it has been so "hands off" in protecting recent Trump rallies that at the polls, "I am not confident police will do their job."

He advised his group to monitor the polls with their guns hidden because, "We want it to be difficult to know you're being watched." He added: "You're not going to be able to tell who's an Oath Keeper and who's not. I'll tell my guys to stay concealed unless they're in a situation that requires them to be overt," such as protesters near the polls wielding guns.

"If we see that kind of behavior, we're going to intervene. We've done it before," he said. "If the cops are doing their job, we'll just stand by. If they're not, we'll step in."

Jim Murphy runs the Black Robe Regiment, an armed, Christian tea party offshoot in Wisconsin. Murphy, 73, a county commissioner with a web design business in Green Bay, communicates with his 300 members online. A man who never leaves home without his 9mm handgun, Murphy said his group is not endorsing violence ahead of the election. But one of his recent tweets called for taking down officials in the federal government.

Earlier this month, he tweeted support for upending the "deep state." He added: "When Will This Happen? We can't call the cops on the cops in Washington so is it really going to come down to us to physically" remove them by force.

Some experts predict armed groups will appear in cities where Trump has alleged voter fraud, such as Philadelphia. Others said they're more likely where they have the most members: the West Coast, particularly the Pacific Northwest. Still others suggest they will head to anti-lockdown and police protest hot spots: Georgia, Kentucky, Michigan, Oregon, Texas and Washington.

Devin Burghart, executive director of the Seattle-based Institute for Research and Education on Human Rights, said they've tracked far-right groups online planning to go to the polls in Michigan, Pennsylvania and Wisconsin. Those who spot them can report to his group via their app and it will alert local legal observers such as the NAACP.

He said armed groups "will refer to it as 'voter integrity' or 'poll watching' but the act of showing up armed is certainly a deterrent to folks showing up to vote," Burghart said.

Heidi Beirich, Georgia-based co-founder of the Global Project Against Hate and Extremism, said violence is more likely to erupt in cities or states led by Democrats that Trump singled out since COVID-19 restrictions began, including Louisville, Kentucky, Detroit, Kenosha, Portland, Oregon, and Seattle.