Law enforcement officials and the watchdog groups that track the self-styled “patriot” groups call them anti-government extremists, militias, armed militants or even domestic terrorists. Some opponents of the largely white and rural groups have made fun by calling them “Y’all Qaeda” or “Vanilla ISIS.”

Mark Potok of the Southern Poverty Law Center, which monitors extremism, said there were about 150 such groups in 2008 and about 1,000 now. Potok and other analysts, including law enforcement officials who track the groups, said their supporters number in the hundreds of thousands, counting people who signal their support in more passive ways, such as following the groups on social media. The Facebook page of the Oath Keepers, a group of former members of police forces and the military, for example, has more than 525,000 “likes.”

President Obama’s progressive policies and the tough economic times have inflamed anti-government anger, the same vein of rage into which Donald Trump has tapped during his Republican presidential campaign, said Potok and Mark Pitcavage, who works with the Anti-Defamation League and has monitored extremism for 20 years.

Much of the movement traces its roots to the deadly 1990s confrontations between civilians and federal agents at Ruby Ridge, Idaho, and in Waco, Tex., that resulted in the deaths of as many as 90. Timothy Mc­Veigh cited both events before he was executed for the 1995 Oklahoma City bombing that killed 168 people, and said he had deliberately chosen a building housing federal government agencies.

Now a “Second Wave” is spreading across the country, especially in the West, fueled by the Internet and social media. J.J. MacNab, an author and George Washington University researcher who specializes in extremism, said social media has allowed individuals or small groups such as Soper’s to become far more influential than in the 1990s, when the groups would spread their message through meetings at local diners and via faxes.

The movement received a huge boost from the 2014 standoff at Cliven Bundy’s ranch in Nevada, where federal agents and hundreds of armed supporters of Bundy faced off in a dispute over the rancher’s refusal to pay fees to graze his cattle on federal land.

When federal agents backed down rather than risk a bloody clash, Bundy’s supporters claimed victory and were emboldened to stage similar armed face-offs last year at gold mines in Oregon and Montana.

In January, dozens of armed occupiers, led by Bundy’s sons Ammon and Ryan, took over the headquarters buildings of the Malheur National Wildlife Refuge near rural Burns, Ore., an action that resulted in the death of Robert “LaVoy” Finicum, an occupier who was shot by state troopers.

Soper has been in the middle of all of it. He says he has tried to be a more moderate voice in a movement best known for its hotheads. He spent a month living in his RV at Burns, trying to talk the occupiers into standing down.