Sitting at his booth in a stickily hot Las Vegas convention centre, a muscly former policeman in his late 30s is draining the last of a Bloody Mary and recounting the horrific things guns can do.

"If you go back to school shootings, it all started with Columbine," says Mike Renaud, in between sips from his plastic cup. "The next guy wants to outdo it. Now they're shooting in movie theatres, malls, anywhere. You turn on the TV and it will say, 'A woman was killed today walking her baby in a stroller in the park,' 'A pregnant woman was murdered.' You leave your house, you've almost got to be on guard. And it's sad. It's sad that you've got to live that way."

But what if you don't have to? What if you, too, have a gun?

"I like to think the more good guys with guns, the better my chances are," Renaud continues. "Cos the bad guys are gonna have them."

That was his logic four years ago when he told his wife, a nurse called Tessa, to get a pistol when she started working nights at the hospital and worried about driving home alone. That was his logic when he decided to keep 10 guns at home in Louisiana, where the couple have six young children. And that was his logic when he booked the 4,800km round trip to Vegas, figuring there was a market for the strip of lace Tessa had adapted to hold a gun when she couldn't find a holster she could wear underneath her scrubs. He called their business Lethal Lace and he is selling the lace holster in a variety of colours for US$54.99 apiece.

Now browsers are stopping at the stand every couple of minutes, but there are still lingering concerns. Is it really responsible, as Tessa suggests, for women to carry a gun around the house inside their pyjamas?

"The world's not safe," she insists, before directly addressing the worries of fellow mothers. "You're not being a bad mother by having a gun around your kids, you're protecting them."

It is my third day at the 38th annual Shooting, Hunting and Outdoor Trade (Shot) Show, and I am beginning to realise that what is really being sold here is not so much pistols and rifles - or even lacy undergarments - but fear.

In the aisles of the world's biggest gun show, which lasts four days in January and brings buyers from police departments and gun shops, they fret about immigration and falling incomes as well as mass shootings. And after the extremist attack in San Bernardino, California, a month earlier, they worry not only about the destruction a deluded loner with a gun could unleash but about armed terrorists living among them.

Across the country, the political campaigns of Donald Trump and Ted Cruz are fuelling distrust of outsiders - and gun sales are surging. With such a litany of worries, there is little prospect of sleep for the 64,000 exhibitors and buyers who have descended on Vegas from every American state and more than 100 countries, even if they stay away from the rows of craps tables in the hotel casino adjoining the convention centre.

So they browse the guns: rows and rows of guns. There is a tactical rifle that can hit a 20-inch target from 1,300 yards: "the newest thing in the Neighbourhood Watch programme", as the salesman jokingly puts it. There is a choice of grenade launcher and a set of four lovingly crafted Perazzi game guns, yours for US$373,000. There is the "femme fatale" air rifle, in a lurid shade of pink. And there is the ultimate accessory for the gun-toting good ol' boy: a bulletproof baseball cap.

Just two weeks before the show opened, Barack Obama said he would use his executive powers to tackle gun violence, after yet another year of mass shootings that could be recalled simply by their locations: Emanuel AME Church, Umpqua Community College. In tears, the United States president recalled the devastation wrought by a gun in Sandy Hook Elementary School, in Connecticut, in 2012, when 20 children died.

But in Vegas, guns are to be celebrated. Here, there is a Glock Appreciation Party, and a man giving out heart-shaped stickers that read "Guns save lives". Often, I discover, gun owners use the same language as their critics, except they aim at the opposite targets, highlighting the mutual incomprehension that characterises both sides of the debate.

One woman says she initially feared it was Obama who would "do something stupid" (like ban all guns), using a phrase familiar from reports of school shootings. Another praises Trump for standing up to immigrants.

BY MID-AFTERNOON ON my first day, I was already lost. The 20km of aisles were so crowded that if you let yourself be distracted for a moment - by a display of camouflage thongs, say - you could no longer be sure in which direction you had been walking. Was the exit back over there, beside the toilets, where a target was affixed to each urinal?

After several wrong turns, I stumbled from the hall and was relieved to come across some natural light, even if the windows afforded only a glimpse of the casino across the road. A fellow refugee, a friendly looking Texan woman in late middle age, introduced herself as Barbara Walker. "I feel very uncomfortable here," she confided. At last, I thought. A kindred spirit. "I feel very vulnerable," she went on, "because I don't have my gun."

Crime is falling. Even though America's population has risen by more than 50 million in the past two decades, the number of reported violent crimes has consistently declined. In 1995, there were 684 for every 100,000 Americans. By 2014, there were 365. The number of rapes and aggravated assaults increased slightly that year, but their instance was still lower than two years previously, and far lower than in 1995.

Demand for guns has been even more consistent: it grows every year. In 1996, there were 242 million firearms in America. In the next four years, another 17 million were bought. By 2009, there were more guns in the country than there were Americans. And still they wanted more.

From a couple of hundred stalls in its first year, the Shot Show has spiralled, too, and this year it accommodates more than 1,600 booths. Returning for a second day, my eyes were drawn to one of them, adorned with a giant poster of half a dozen women wearing black shades, doing their best to look menacing. "Gun tote'n mamas," it screamed. The company sold everything from zebra-stripe clutch handbags to tote bags, all with holsters. "We get people telling us, 'It was a carjacking and your bag saved my life,'" said Claudia Chisholm, the company's owner.

Chisholm, a surprisingly shy woman who is just four foot, eight inches tall, turned out not to be a mother (she is a "proud aunt") nor, until recently, even "gun-tote'n". That changed last summer, when she spent two days learning to shoot a handgun at a range in Colorado.

"The feeling was actually really empowering," she said.

The number of Americans with "concealed carry" permits - allowing them to take a gun around with them in a handbag or hidden under clothing - has more than doubled since Obama was elected, leaping to almost 13 million, according to one study.

Once, the stereotypical gun owner would be rural, a hunter or a farmer intent on pushing America's frontiers and keeping his land safe. Since the 1980s, though, the "right to carry" movement has exploded, arguing that Americans cannot be restricted to the God-given (or, at least, constitution-given) right to own a gun, but must be allowed to carry it around with them at all times.

Several men I meet at the show own more than one gun, reflecting the manufacturers' ingenuity in supplying a new firearm for each purpose: some for hunting, a few for target shooting, still others for self-defence.

"I've got so many at home, I don't know what to do with them all," said a man who admits to owning 100 guns.

Another cannot recall exactly how many he owns.

"Quite a few," he said. "Never enough."

Others, especially urban women, own only one: a pistol for their handbag, which they have sometimes not practised with for a couple of years.

Neither group seems to have heard the good news about the crime rate.

"The world becomes less friendly every day," Chisholm said.

"All you've got to do is read the papers," said Branden Irwin, a buyer for Wild Bill's Old West Trading Company, in Elk Grove, California. "People are panicking."

They panic the most about mass shootings. The counterintuitive argument, which is repeated often over the four days, runs like this: if somebody planning a shooting spree knew everybody was armed, he might think twice. Even if he went ahead, he would be "taken down" before he claimed too many victims. This is the same argument that fuels calls to arm teachers when children are shot in class.

So the self-selected good guys are racing to buy guns - and they need some way to carry them. Hence the explosion in accessories: Gun Tote'n Mamas, Lethal Lace and - a business I discovered when I finally reached the far corner of the first hall - UnderTech Undercover.

This stall sells briefs and tank tops, a polyester and spandex mix with a pouch for your gun.

"You're going to wear underwear anyway," as the owner, a tall, blonde Californian called Tammy Magill, has it, "so why not put a holster on it?"

Women made up only a fifth of her customers when she started the business with her husband 10 years ago; now they are the majority.

"Nobody wants to be murdered and raped, and you want to carry a gun," said Magill, instructing her attractive female staff to show me where each had hidden their pistol.

But does it all have to be quite so fashionable? Doesn't this risk glamorising guns? Magill enthusiastically agreed.

"I don't see why I shouldn't be able to glamorise it," she said. "It's my pastime."

ALTAMOND WILLIAMS, 77, IS mad as hell and he wants everyone to know it. He is sitting in a smart blazer and tie behind half a dozen display stands full of bumper stickers. There are 800 in total, he says, in all manner of offensive varieties. "WARNING!" one hollers. "DUE TO PRICE OF AMMO INCREASE, DO NOT EXPECT A WARNING SHOT."

All of this, I say, is a little provocative.

"I have sex three to five times a week and drink half a gallon of Scotch," he says, as if determined to tell me something truly provocative. "That's not bragging, that's just the facts." He beams when I ask where he has come from. "The oldest country in North America: the South." In fact, he explains, he inherited his unusual Christian name from his grandfather, who fought in the civil war. When will he retire? "When I dah."

Although Williams is unusually forthright, many of the other gun owners at the show are also old, white and convinced their culture is under threat. The industry might have launched a few ranges for women, but this is emphatically a man's world. In one 10-minute stretch I count 209 people stepping off one of the escalators. Of these, 169 are men and 40 are women. All but 15 are white.

This, then, is the white American man's "safe space" - to use the hated liberals' jargon - where their power goes unquestioned and everyone agrees on the primacy of that holy trinity: God, guns and America. Inside the halls, old-fashioned skills are revered: people queue to see a gun-spinning demonstration and thank men who wear "Vietnam veteran" caps for their service. None of the rifles is loaded, but men cannot resist aiming them and yelling: "Boom! Boom!"

Those who return each year rekindle old friendships and, after a couple of days, people begin to wave at me as we pass on the escalator. In the words of a buyer called Hugh McAllister, "You're not going to find more peaceful, friendly people."

In the terrifying world outside, though, their once unassailable economic and political might seems to be ebbing fast, chipping away at their self-confidence. In four out of 10 American families, the breadwinner is now female, while whites - male and female - are predicted to be in the minority by 2044.

The housing-market crash and the global economic crisis that Americans call the "Great Recession" meant that, by 2014, the median income of middle-income Americans was 4 per cent lower than it had been 14 years earlier. Over roughly the same period, their median wealth fell by 28 per cent. Meanwhile, their country lost ground, too, to rivals such as China: in 2014, the US was eclipsed as the world's biggest economy for the first time since 1872.

Such fears are brought into sharp relief when I stop a man in his late 20s who is heading home for the day, so struck am I by his T-shirt. "I'M NOT VOTING FOR MONICA LEWINSKY'S EX-BOYFRIEND'S WIFE," it declares. Jonathon Saltzman turns out to be far subtler than his slogan. But the 28-year-old, who manages an ammunition shop in Temecula, California, agrees that show attendees are angry, and not just the older ones.

"We grew up being told certain things: you go to school, you go to college, you get a job. This is the American way," he says - adding bitterly, "Not so much any more. Our school systems are failing, we have no jobs. I'm a certified welder but I'm a manager at a retail store because I can't find a welding job. It's depressing to know that our work is being sent overseas - we're just ass backwards right now." Gun ownership provides at least one reassuring way to assert masculinity.

"Really," says Saltzman, "it's a way of life."

ON MY FINAL DAY at the show, I eat breakfast in the press room, where some journalists wear cowboy hats and the multicoloured keys of one reporter's laptop make up the Stars and Stripes. Two men in late middle age sit across the table from me, talking about how their country has changed since they were young, when they were "all invincible".

"If men can't be a little crazy standing up for what's right," his companion replies, "we can't be men."

When Obama gave that speech about guns at the White House, he borrowed a phrase from Martin Luther King: "We need to feel the fierce urgency of now," he told reporters, "because people are dying." At the Shot Show, they feel the fierce urgency of now, too. After all, the American gun owner's biggest and oldest fear is the federal government.

Washington is the enemy from which their arms were first intended to protect them, the whole point of their cherished Second Amendment, the constitutional right to bear arms. Many here argue that guns are as essential for defending individual liberty as an army is to keeping a country free.

"Guns are freedom," says one white-haired gun-shop owner.

And now the president is trying to take them away. Well, actually, he isn't. He has outlined a series of relatively modest proposals, such as clamping down on private sales that see some guns exchanged at shows without background checks and straw purchases in which weapons are bought via intermediaries. He has not questioned the link between the right for a group of citizens to defend themselves against federal tyranny and the right of a Texan to take a pistol with him when he goes out for a hamburger.

But, as I roam the halls, the reinterpretations of this executive action grow wilder. One buyer says it is unconstitutional, another says it would spark "one of the biggest revolts that this country has ever seen". A third declares, suitably outraged, "Then only criminals will have the guns!" The man behind all of this is, variously, a socialist, a Muslim, "anti everything that's American".

"Obama is a secret agent for al-Qaeda," says one man. "There's no other way to explain his actions."

The irony is that Obama is a great gun salesman. For the giant corporate manufacturers and the small-town gun shops, fear means profit. Every time the president condemns another mass shooting or talks negatively about the gun industry, more Americans rush out to arm themselves, fretting that they may not be able to do so soon.

Since Obama first took office in 2009, the shares of gunmaker Smith & Wesson have surged by about 700 per cent, according to CNBC. Over the same period, Fox News gleefully claims, Americans have bought 100 million more guns.

"Right now, there's a lot of jobs out there," says Joe Pfeifer, a gunsmithing student from Kansas on a college trip to the show. "It cycles with the presidential elections. If it looks like a Democratic nominee is going to win the election, then everybody goes out and wants to buy a bunch of guns, so there's a bunch of jobs for gunsmiths."

But there are too many dollars riding on guns for manufacturers to enjoy this short-term boom and risk guns becoming harder to buy - and harder to sell. And so, having long supplied the precision-engineered answer to its customers' fears, the industry itself is now in a state of high anxiety. Not only does Obama have them in his sights, but Hillary Clinton has vowed that, if elected, she will "take on the gun lobby".

"There's apprehension," says Barbara Skinner, a freelance editor who has been coming to the Shot Show for 35 years. "A lot is going to depend on the election."

In his 69 years, Trump has played many roles: hard-bargaining developer, beauty-pageant impresario, reality-television star and, most recently, self-styled voice of the silent majority. But even Trump admits "gun-toting outdoorsman" would be a bit of a stretch. The billionaire, who likes to return home to his bed in New York every night, used to support longer waiting periods to buy a gun. Once, asked about hunting, he replied, "I, em, like golf. I don't do that."

All of which has not prevented him casting himself in the role of the industry's staunch defender, helped by his sons, Donald Jnr and Eric, who, pictured recently with a dead leopard on Instagram, were taught to hunt by their maternal grandfather, and invited the press to hunt with them in Iowa the week before the state held the first caucus of the campaign season. (Back in 2012, Donald Jnr seemed less convinced of his father's outdoorsy credentials, admitting the elder Trump "really doesn't understand why Eric and I hunt".)

Whether or not his background appeals to Shot Show types, the negative message of his campaign fits the mood perfectly. "Make America great again!" Trump always insists, before elucidating each of the country's present ills. Sarah Palin, who has endorsed the Trump campaign, once said that were Jesus alive today, he would fight to defend the Second Amendment.

"Right-winging, bitter clinging, proud clingers of our guns, our God, and our religion, and our constitution," she said of her people, announcing the endorsement. She could have been describing the Shot Show.

And then, on the final night, an excited whisper goes around the convention centre: he is here. I have no idea where but I follow a father and son across the hotel's casino floor as they congratulate each other on wangling an invitation. The sight of Secret Service agents (their jackets read "Secret Service") at the door of the Venetian Theatre gives the game away.

Trump is to speak at the industry gongs known as the Golden Moose Awards, celebrating such TV shows as GunnyTime and NRA: All Access. Before he appears, jokes about Democrats abound.

"One more year of Obama?" asks Rob Keck, the director of conservation for a huge chain of hunting supply stores, before presenting an award. "I think we ought to give him 25. Yeah, 25 years to life."

Trump had spoken under the glistening three-tier chandelier a month earlier, at one of the Republican debates, but this time he has brought reinforcements.

"Stay out here, Don!" he implores, as his warm-up-act son tries to slip backstage. "Eric, come on!" They stand either side of him, human props in case the crowd should question his commitment to guns.

"We're going to protect the people in this room and what they love," he booms. "And you know what you love. I love it." He points to Eric. "This one loves it." He points to Donald. "That one loves it." Then he addresses his audience's concerns. They fear outsiders. He promises to build a wall. They fear America's decline. He promises to start winning. Most of all, they fear losing their guns. "The Second Amendment is 100 per cent protected," he yells. "100 per cent."

Trump speaks for less than five minutes, but the crowd still manages to interrupt him 16 times for applause, and he only leaves the stage after a lengthy standing ovation.

Whether or not the Trump campaign prevails, the fear on which it thrives will not pass so quickly. It is already well-established among the good guys, the guys with the guns, that armed coalition of the bitter, the scared and the plain paranoid. And while their hero may never get his hands on the nuclear button, they already have theirs on the trigger.

​​Telegraph Magazine