Not long ago Republican Phil Scott was one of the most popular governors in America, poised for a comfortable re-election in November. Then, after a possible school shooting was discovered by police in Vermont, he decided to support sweeping gun-control legislation - and has reaped a political whirlwind.

The Vermont governor stands at a lectern in front of the state capitol building in Montpelier on a grey, blustery April day earlier this year. His wife and various politicians, officials and dignitaries stand behind him. Before him, a motley crowd. Some are cheering; others are angry - and loud.

He's talking about gun control, a subject that touches raw nerves across the US, even in serene, bucolic Vermont. Perhaps especially in Vermont.

"On February 16," he begins to a crescendo of jeers, "I was in my office preparing for the day ahead, when everything changed."

He relates how he received an affidavit that morning detailing the arrest of 18-year-old Jack Sawyer, who law enforcement officials said was in the midst of plotting a mass shooting at a high school in Fair Haven, a small town in the western part of the state.

A friend of Sawyer's had informed police of his plans - and how he praised the attack at a high school in Parkland, Florida, that claimed the lives of 17 students and teachers just days earlier.

"That's fantastic," he texted her. "I 100 percent support it." He called the Marjory Stoneman Douglas High School massacre - which shocked the American public and prompted teen-led anti-gun protests across the nation - "natural selection taken up a notch".

The police searched Sawyer's car and found a shotgun, ammunition, a gas mask and books on the 1999 high school shooting in Columbine, Colorado, in which 13 students died. He also kept a diary titled "The journal of an active shooter", in which he listed those at his former school who he wanted to kill.

When police spoke to Sawyer, he confirmed that he was planning an attack and said it was his intention to surpass the record of 32 fatalities at the Virginia Tech University shooting in 2007.

"As I read the 13-page affidavit," Mr Scott tells the assembled crowd in Montpelier, "I was alarmed to learn just how close we came to the same tragic fate the people of Parkland faced."

After concluding his speech to a cacophony of applause and more boos, he turns to a desk set up for the occasion and signs a package of sweeping new state-level gun-control rules.

What changed?
Vermont raised the age to purchase firearms without first taking a hunting safety course from 18 to 21. It capped the number of bullets a gun magazine can legally hold at 15 for pistols and 10 for rifles.

Bump stocks, the after-market devices that allow a semi-automatic weapon to rapid-fire like a machine gun - used to tragic effect in the Las Vegas mass shooting of September 2017 - were banned in the state.

Private firearm sales, such as those at gun shows, now required the same purchaser background-checks as gun-store transactions.

With a court order, law enforcement could confiscate guns from individuals considered an "extreme risk" of violence or those arrested on domestic abuse charges.

It was a laundry list of the kind of gun-control policies that activists have been advocating on a national level for years, to no avail.

With the stroke of the governor's pen, Vermont - a largely rural state that hunters, sportsmen and firearm enthusiasts have long celebrated as a gun-rights haven - moved to the forefront of reform.

And Mr Scott, a Republican in his first term in the state's top office, was the unlikely man leading the charge.

'I own it'
Six months after his April speech, the anguish of that February morning - and the days and weeks that followed - still plays out on the governor's face and in his hands, which he squeezes together as he talks.

"We're such small state," he says. "We know our neighbours. How could it get to this point?"

Mr Scott is now sitting at a nondescript table in a nondescript office by an airfield in Barre, his tiny home town near the only slightly larger Montpelier (the smallest state capital in the US, which boasts that it's the only one without a McDonald's).

Mr Scott is running for re-election in November, and the office is his campaign headquarters. The only indication, however, is a small sign in the back window of a building shared with a hearing centre and an eye doctor. A campaign van is discreetly parked in a rear lot.

"I came to the realisation that we aren't insulated from this type of tragedy," he says. "And it was sobering, to say the least."

In his past campaigns - for governor and, before that, for lieutenant governor and state senator - Mr Scott had expressed support for the state's lenient gun regulations. The businessman and former stock car driver says he owns guns himself and completed a National Rifle Association safety course when he was 11 years old.

The near miss in Fair Haven changed his mind.

"I chose action over inaction, and it wasn't easy," he says. "I went into it with my eyes wide open."

So Mr Scott turned to the Democratic-controlled state legislature and worked to pass new laws. His eyes may have been open; he may have known the political price he would pay - but even so, the severity of the consequences has been stunning.

A Morning Consult poll taken before his gun-control push found Mr Scott to be one of the nation's most popular governors, with a 44% net approval rating. By summer, his net positive support had dropped to 5%.

The change is almost entirely because independents and members of his own party, whose positive view of the governor fell from 67% to 41%, deserted him.

In August a little-known grocery-store owner, Keith Stern, challenged Mr Scott in the Republican gubernatorial primary and, on a shoestring campaign budget, won 33% of the vote.

"My supporters were not happy with my decision, and they exercised their First Amendment [free speech] right," Mr Scott says. "I'm reminded of it almost on a daily basis."

The governor says he carries a fact sheet about the gun law so he can explain to critics what it does - and does not - do. He also likes to show them a copy of the Sawyer affidavit so they can "see what I saw in real time" and, perhaps, understand why he took the steps he did.

"I own it and face my adversaries, once friends, on this issue," he says. "But it's not easy."

'Absolutely betrayed'
It didn't appear as though there was much understanding among the gun rights protesters in the Montpelier crowd back in April.

Many were decked out in bright orange hunting gear. They hoisted signs and called the governor a liar and a "gun-grabber". They chanted "traitor" and shouted about the Second Amendment constitutional right to bear arms.

One man had a plastic knife sticking out of his back.

The public signing ceremony didn't have to happen. Mr Scott wanted it - something he says could help with the healing process after the acrimonious legislative fight.

"I thought it was necessary for me to face my adversaries so that I wasn't hiding behind closed doors and signing this," he says. "So they knew that I wasn't playing politics."

Ed Cutler, president of the Gun Owners of Vermont, was among the protesters and has a different take on the governor's decision.

"He went out there and literally rubbed our noses in it," Cutler says. "We were absolutely betrayed. A lot of people were hurt. A lot of people were angry."

Cutler recalls the bill signing while at a friend's private gun range near his home in Brattleboro.

It's a serene scene. The babbling of a small stream and the rustling of wind in the leaves of the trees are broken only by the occasional report of gunfire, as Cutler - who holds a world record for pistol marksmanship - and his friend take their aim against targets set up against nearby hill.

He says the governor, who he once considered a friend, lied to him.

"We relied on Phil to defeat a bill, and he turned around and helped them get it," he says. The governor, he continues, clearly was making a political decision to court liberal voters and endear himself to national gun-control groups - a move that backfired.

And all that talk by the governor about the 13-page affidavit and what-would-you-have-done hypotheticals?

Sawyer, he says, committed no crime. He had a shotgun, a handful of shells and a lot of big talk, but there was no indication he was actually going to follow through on it.

In April, he notes, the Vermont Supreme Court ordered prosecutors to drop the felony attempted murder charges against Sawyer because "planning" was not the legal equivalent of "attempting.

"They took away the civil rights of 625,000 Vermonters for the theoretical maybe of one misuse," he says. "In that case, I should be in jail because I have an armoury. It just doesn't hold true. We have a presumption of innocence."

(Sawyer has since been released from jail pending a trial for "criminal threatening" - a development that led to a 25% drop in attendance at the Fair Haven High School.)

On a table, Cutler sets out a few of the more than 100 guns in his collection. Many were once rusting relics that he has painstakingly restored to near-original condition. Some are worth thousands of dollars.

He says he fears that Mr Scott's gun laws are a first step that will lead toward state efforts to confiscate his treasures - a "prohibition by attrition" strategy pushed by deep-pocketed anti-gun activists like former New York City Mayor Michael Bloomberg.

Cutler points to a Sharps single-shot carbine from the US Civil War, an 1885 high-wall Winchester - he calls "priceless" - and a Ruger 10/22 with a legal 10-round magazine.

"If this was a 15-round magazine and I give it to you," he says, "both of us are going to prison."

He owns a replica of an 1860 Henry carbine, which holds 16 bullets. Originals are worth $20,000 and up - and they're now illegal to sell or transfer in Vermont.

"Can you imagine taking a $200,000 gun and having to trash it?" he asks. "This is your kid's inheritance."

He pulls out a rifle barrel he uses for demonstrations, to show how switching out the firearm's stock can turn it from an ordinary-looking hunting rifle to the type of "assault weapon" frequently associated with mass shootings.

"It's still the same gun," he says.

Cutler gives guns to friends, sometimes as gifts and sometimes in exchange for help. The Vermont law that now requires all gun transactions to be accompanied by background checks would have "ruined the moment".

Cutler minces no words when he talks about gun-control advocates. He recently was accused of threatening an anti-gun politician by saying he wanted to "eliminate" her.

"What I wanted to do was eliminate her legislatively," he says. "We have eliminated legislatively, electorally, lots of candidates over the course of 20 years."

Now he wants to (electorally) get rid of Mr Scott.

"He's blue collar. He's one of us. I thought he was good for his word," Cutler says. "We had nothing bad to say about him. And now we have nothing good to say about him."

A radioactive issue
The challenge for Cutler and his fellow pro-gun activists is the governor's opponent, Democrat Christine Halquist, is equally supportive of gun-control efforts. They're left focusing on state senate races and hoping to hold the line until they can mount a more serious primary challenge in two years' time.

The challenge for Mr Scott is that, with tepid support from Republicans and independents, he may have to rely on Democrats to carry him to re-election in November.

If there was a bit of silver lining in that Morning Consult poll showing Mr Scott's precipitous approval drop, it's that Democrats actually like him, with 61% approving of his job performance. But do they like him enough to vote for him?

Public head-to-head polls for the Vermont governor's race are non-existent - the small-state matchup hasn't attracted much national attention. According to Vermont Democratic Party Chair Terje Anderson, however, their internal polls show a tight contest.

"I think she started out as an underdog," he says of Halquist, "but if we've got enough Democratic enthusiasm, I think she's got a good chance."

He adds that the national politics - the Donald Trump effect - has spilled into local politics, making it tough for Republicans in liberal states like Vermont. Mr Scott, he says, has also hurt himself with Democrats by vetoing a minimum-wage increase and a paid family leave bill.

"I was there at the statehouse when he signed that bill, and I thought it was a very brave thing to do, and I give him lots of points for that," he says. "But it only passed because there was a strong Democratic majority in the legislature. We think we can get a lot more done with a Democratic governor and a Democratic legislature."

Complicating the matter is the fact that Halquist would become the first out transgender governor in the US. Liberal voters in Vermont, the first state to legalise same-sex marriage, may be keen to make history again.

Whether Mr Scott prevails or not, his story illustrates exactly how difficult it is for Republicans - any Republicans, in any state - to forcefully advocate for gun control.

During a governor's debate in Rutland two weeks ago, Mr Scott frequently came down on the liberal side of hot-button national political issues.

He said manmade climate change was real - and governments should take action. He expressed support for a Medicare-for-all universal government healthcare system. He spoke of the benefits of immigration.

Those views, while out of step with national Republicans, have carried little political price in Vermont. The gun issue, on the other hand, is radioactive.

"I believe our society and our country are becoming more polarised every single day, and that divide is growing deeper for those of us in the middle," Mr Scott says. "It makes it that much more difficult because we're open-minded and willing to make some difficult decisions. And when you do that, your popularity can go up and down, depending on the day."

That may be so, but in a campaign season where Republicans are playing defence across much of the nation, there are a handful of Republican governors who appear poised to weather even the fiercest of Democrat-blue storms.

In traditionally liberal states of Massachusetts, New Hampshire and Maryland, Republican governors are running for re-election who remain popular. The key to their success seems to be their moderation and willingness to work across party lines.

Eight months ago, Phil Scott was poised to be one of them.

Then, on 16 February, everything changed.