What's happening here is actually a long battle over farmland that's been repurposed as federally-managed space. Throughout the 20th century, the act of using government land for cattle grazing and farming became the bureaucratic equivalent of a Nickelodeon GUTS event -- complete with an ever-changing Aggro Crag of policies and restrictions. In short, Uncle Sam yoinked the land from under these ranchers' feet and made them tap dance to get it back.
See, the reason the Oregon militiamen feel ownership over this land is because it was first given to ranchers by the U.S. government back when we were still expanding into the totally up-for-grabs West. This absolutely uninhabited area was then distributed to farmers to drum up economic growth. Everybody was a winner! But by the end of the 1800s, the attention shifted and the land was taken back, which is what the Bundy family behind the Oregon standoff is still ultra-miffed about.
If you think it's silly that I'm making fun of the militia like this, then prepare to bust a nut over the Sovereign Citizen movement, which practices the disobedience of federal and sometimes local laws under the vague belief that the United States exists like a corporation we can choose to ignore. This was the argument rancher Cliven Bundy used back when he didn't want to pay $1,000,000 in accumulated fines, and a common tactic for crazy people trying to get out of various crimes.
To get a sense of what the Sovereign Citizen movement is all about, take a look at the quote below. You can reread it a couple of times if you want, but it still won't make any sense.
That quote isn't from some robe-wearing Grand Minister of The Bunker, but from Stewart Rhodes, the founder of a collection of retired law enforcement and military personnel called the Oath Keepers. According to their website, their mission is to uphold the U.S. Constitution by any means necessary, including war with the federal government. And while there's nothing wrong with questioning and challenging the law, their bias leans less on the side of a constitutional "checks and balances" and more on commie paranoia and misplaced nostalgia for '50s America. A quick scroll through their site reveals everything from an essay about the good ol' days, when "we weren't taught about The Planet [sic]" to carefully chosen news stories designed to incite fear of refugees and Muslims.
Let's look at a two-part Oath Keeper essay titled "Are You Ready To Join The Resistance?" which warns people of the upcoming economic collapse and martial law. Their solution, of course, is to arm yourself, learn to survive away from cities, and prepare for "hungry gang members" knocking at your bunker. But hey, but at least this stealth Fallout fanfiction is free to read, right?
Sovereign Family Network