In the Republican presidential debate last Saturday, Ted Cruz laid out a dark scenario to demonstrate the need for a beefed-up missile defence system – the same one Rick Santorum and Ben Carson had raised before him in earlier debates. He said that North Korea was working on a satellite, which could spell doom for America:

“As it would orbit around the Earth, and as it got over the United States, they would detonate that nuclear weapon and set off what’s called an EMP, an electromagnetic pulse which could take down the entire electrical grid on the eastern seaboard, potentially killing millions.”

The very day before Cruz spoke, in the tatty, cavernous but crowded Expo Idaho Center in Boise, speaker and entrepreneur Ben Gilmore laid out a much more elaborate version of the same catastrophe.

In his reckoning there were distinct phases and types of EMP attack, a range of dire consequences depending on where you chose to live, rundowns on the technology of attack and response, and details on a range of possible aggressors.

Speaking to a rapt audience at prepper expo SurvivalCon, Gilmore pointed to a projected map showing much of the North American continent swathed in a deep red.

“An EMP bomb 300 miles up gets all of the United States, and parts of Mexico and Canada. This is the worst-case scenario, and it is the most probable because currently the military model is that if we are struck by a nuclear bomb we are supposed to absorb it.”

The apocalyptic prediction was thus spiced with a factoid that has long exercised millennial thinkers on the right like Joel Skousen – Bill Clinton’s change to the United States’s deterrent posture at the end of the cold war.

Ben Gilmore at SurvivalCon. Photograph: Jason Wilson for The Guardian

This mixture of End Times thinking, geopolitical speculation and rightwing ideology was repeated not only in the other formal presentations, but in conversations on the floor of the Expo Center.

Randy Pons, an otherwise cheerful middle-aged manufacturer of prefabricated fibre-glass survival shelters, darkened as he told me that he worried about Putin. “He said he would bomb Yellowstone. He’s smarter than [Barack] Obama.” Every tapestry of disaster had a visible thread of blame. And mostly that opprobrium was reserved for liberals, secularists and Democrats.

Back at the podium, Gilmore had massed evidence from all corners of the internet for his projections of disaster, including a 2011 video report from the Christian Broadcasting Network which claimed that Iran would have the capability of a missile-launched EMP attack by 2015.

He was not just concerned about North Korea – “Iran, Russia and China” are capable of unleashing the same weapons, especially since Obama has been treating them with kid gloves. When it happens – and for him it’s not an “if” – he predicts the grid will be down for up to 10 years.

“Life will go back to the 1850s” unless we prepare. But how? First with faith – “above all follow God” is Gilmore’s best advice.

But also – in a stroke of luck – Gilmore’s own company, Techprotect, makes “Faraday bags” in which electronic items can be shielded from electromagnetic pulses. The company boasts that they are “military grade” and can save everything from cellphones to generators.

You will never be hungry. Photograph: Jason Wilson for The Guardian

Wrapping up your gadgets is just one part of the prepper prescription. Gilmore’s father, Jim, known on YouTube as ldsprepper, has a well-trafficked channel where he advises on growing food, arming yourself and creating a sustainable, defensible, self-sufficient lifestyle.

Both men – like most of the vendors on the floor – are Mormon. In part this is because Mormons are relatively overrepresented in the intermountain west. Around a quarter of Idahoans belong to the Church of Jesus Christ of Latter-day Saints (LDS), and it’s more like 60% in neighbouring Utah.

But Mormons also play a central role in the prepper movement because they have inhabited the practice and the mindset longer than anyone else. Laying aside a year’s worth of food, water and money in case of emergency is a matter of Mormon doctrine. The church lays aside communal supplies in so-called “bishop’s storehouses” throughout the country.

And since the church’s beginnings, millenarian beliefs have been a constant presence and temptation. Those beliefs were evident in a speech given by Charla Conove, who offered a presentation heavy with diagrams, astronomical charts, and numerical coincidences, about clues in Mormon scripture, the Book of Revelation, and the heavens concerning the apocalyptic “Blood Moon prophecy”.

This line of thought – which prophesies the imminent end of the world partly on the basis of astronomical events – was popularised by Mormon author Julie Rowe. Belief in the prophecy became so prevalent late last year that the official LDS church was forced to condemn it.

Such thinking raises the stakes immeasurably on the ways in which we differ in politics, lifestyles and belief. There’s not much room for compromise in a mindset that divides the world so starkly between good and evil, and sees the fate of the world at stake in political disagreement.

David Swickard from the Idaho militia. Photograph: Jason Wilson for The Guardian

While survivalism has undergone something of a makeover recently – with reality shows making it seem like harmless fun, and news outlets insisting that lefties can do it too, the Idaho show showed continuing strong links persist between prepping, religious fundamentalism and the far right.

Other speakers at the conference included David Swickard from the Idaho militia. Although he tried to distance himself from the actions of the Bundy bunch occupying the Malheur national wildlife refuge in Oregon, he referred to them as “patriots”.

He also offered a similar take on the constitution to theirs, and a similar rationale as that given the militia to that of far right groups since the 1990s. The militia was “recognised in the constitution”, it included “all able-bodied citizens” and stood against “all enemies foreign and domestic”, including the federal government.

It’s not news that the Republican party has moved far to the right during this campaign, and that populists like Donald Trump and evangelicals like Cruz are leading the pack. And it’s equally unsurprising to see the prepper industry stoke the fears that sell its products.

What is unusual is to see what might once have been seen as a fringe group signalled so obviously by presidential candidates. It’s also striking that this stark point of view can draw thousands to a trade show in a provincial city. Our politics may be being scrambled more thoroughly than we think.

