The cast of characters brought to life in the songs of multiple Grammy winner Jason Isbell are often working-class Americans trapped by bad jobs and bad decisions, dealing with life’s disappointments.

Some of them are running away, getting out while they can, like some Bruce Springsteen archetype. Others are digging in, not daring to leave, facing away from the window in the bar on a Friday night and convincing themselves they could be in any town.

Such unflinching and unsentimental blue-collar portraits win Isbell awards and admirers, including Man Booker prize-winning author George Saunders, who has called him a musical genius.

But some of Isbell’s fans were not so happy to see this white southern man – he was brought up in deep red Republican Alabama – outing himself as a Democrat last year by stumping for surprise winner Doug Jones in his Senate race against Roy Moore, the Republican accused of sexually assaulting teenage girls.

The “shut up and sing” contingent are still out there on social media, urging him to “go live in Iran” and not be ashamed of his roots. Isbell usually manages to laugh it off or hold his ground without getting sucked into the vortex of rage, but did he worry about a backlash at the time?

“Well, the other guy was a pedophile, so it wasn’t a difficult decision to make,” he told the Guardian. “It was pretty obvious that everybody in the whole world should have come out in favour of Doug Jones.

“I think a very small fraction of my audience was shocked by that and I think it’s very easy to hear loud voices, especially online. Just because it’s easier to pay attention, to focus on the people who are yelling at you on the internet, that doesn’t mean there are a lot of them, there really aren’t. My audience is never divided down the middle.”

People had warned him he would lose half of his audience, but Isbell rejects the idea.

“If you are selling a commodity, if the music you are selling is similar to Frosted Flakes, then you are gonna have a pretty even mix of Americans on both sides of the aisle buying your product,” he said. “But if you’re honest and you have some kind of a story that means something, there’s no way that split’s going to be 50/50. So yeah, a few people got pissed off, but I don’t care! The guy was a pedophile! It’s collateral damage.”

As campaigning for November’s midterm elections gathered pace, Isbell was recently branded part of the “unhinged left” by the Republican party after playing at a rally in support of Phil Bredesen, a Democratic candidate hoping to win a tight Senate race in Tennessee.

Speaking by phone before a show in St Louis, Missouri, Isbell said: “I got a kick out of that because it was such a disaster on their part.”

A recovering alcoholic, Isbell has been sober for more than six years, a period during which he got his life and career spectacularly on track.

He married musician Amanda Shires, became a father and produced three albums – Southeastern, Something More Than Free and The Nashville Sound – which all won album of the year accolades at the Americana Music Awards, along with four Grammys.

“The music I have made that has given me some success in this business is all pretty much about becoming, and staying, hinged,” he said. “So whoever called me unhinged hasn’t paid attention to the last three albums I’ve put out.

“Phil’s ahead by two points in that race right now. I’m not going to say that that had anything to do with that, but there might have been a few people who thought: ‘OK, well if these people are stupid enough to call this recovering addict, whose pretty much probably too preachy in all honesty, if they are going to call him unhinged, then they don’t have any idea what people are thinking.’”

Jason Isbell and Amanda Shires perform at the Americana music festival and conference in Nashville, Tennessee, on 12 September. Photograph: Erika Goldring/(Credit too long, see caption)

Growing up in a far corner of rural Alabama, Isbell was exposed to the ingrained everyday prejudice of an all-white southern community. But he was also incredibly lucky to be close to the Muscle Shoals recording studio, where a generation of local musicians like David Hood and Spooner Oldham played on 1960s soul masterpieces with Aretha Franklin, Mavis Staples and Etta James and where, in the 1970s, many rock standards were recorded as Bob Dylan, Rod Stewart and the Rolling Stones came to town.

“I got lucky growing up there, because of the musical influences that I was exposed to,” he said. “There were also some things that I struggled with. When we were playing little league baseball, we had to have the Confederate flag on our uniforms. That was how they determined whether or not the balls were official or the bats were the right weight and size; if they were stamped with the Confederate flag, then we could use them in the game.

“Most of the people where I grew up had no clue that that would be offensive to anybody and there weren’t any black kids around, so how would they know?

“I knew there was something wrong when I was a kid, but I really understood it better when I went to college in Memphis. When I got out of high school and I was around all kinds of different people in a fairly urban campus … and I quickly realised that those things weren’t OK and I realised why.”

Some of his songs – like the Grammy winner If We Were Vampires – are deeply affecting. Time seems short and love, however deep, is ephemeral and counting down. Maybe people drawn to those universal themes or the odd slide guitar solo just weren’t expecting politics to intrude.

Yet for those who have been paying attention, Isbell’s work grew notably more political after Trump won in 2016, and after becoming the father of a little girl.

Hope the High Road, with its “There can’t be more of them than us” rallying cry, is a candidate for the best protest song of the Trump moment – pissed off without being too obvious – a call, as he puts it, “to fight as hard as you can possibly fight, without losing your dignity”.

He sounds at his most angry in White Man’s World, which deals with white male privilege, the southern legacy of racism, and the sexism of the Nashville music scene – drawing hope and inspiration at the end from the fire in his little girl’s eyes.

“It’s probably as angry as I allow myself to be now, and I don’t know if that’s necessarily a healthy thing psychologically. I should probably let myself feel my anger a little bit more,” he said.

“But there is a point of diminishing returns that we have to be very aware of these days. If you go beyond it, you wind up spending all day yelling on Twitter and then nobody’s listening to a thing you say. Or you get in a fistfight with somebody on a sidewalk because somebody’s wearing a Make America Great Again hat. And fistfights aren’t generating votes.

You have to say something, and that’s how the political climate functions right now. It’s an impulse to say something when I feel like it’s wrong Jason Isbell

“There is always this low simmer inside me right now that there are so many obvious injustices in American society that could just be fixed if everybody opened their eyes and looked at it. Not be afraid to look and not turn away after a couple seconds because it’s uncomfortable.”

Headlining at the famously activist Newport Folk Festival this summer, Isbell was joined onstage by David Crosby, for a version of Ohio, Crosby, Stills, Nash & Young’s 1970 protest song about the national guard shooting dead four students at Kent State University during a mass demonstration against the US bombing of Cambodia.

“The thing that surprises me is that we haven’t made a whole lot of progress since Crosby, Stills, Nash & Young were originally singing that song. You would have thought that we would have got some of those problems sorted out by now, but there is still just as much of a need for protest as there ever was.”

Isbell, who plays in New York on Saturday at a festival curated and headlined by the National, spoke onstage that day in Rhode Island – about the duty and responsibility artists and their audiences have to uphold a tradition of speaking out. Does he feel an obligation to use his platform?

“I think so. Probably the burden is more of a responsibility as a person than as an artist. I think I’m lucky enough to have people listening,” he said, “but it’s the same kind of situation as if you see somebody getting beat up in a back alley because of their race or their gender. You have to say something, and that’s how the political climate functions right now. It’s an impulse to say something when I feel like it’s wrong.”

I’m not ashamed of a damn thing. I always play that song, and a couple thousand people bought tickets and showed up knowing they’d hear it. I’d call that a great reception. https://t.co/LNihOz2ZB9 — Jasoñ Isbell (@JasonIsbell) September 24, 2018

In a recent Rolling Stone interview, Isbell said of conservative Christians in rural America who voted for Trump: “God is gone from those people.”

Does he now think that was too provocative? “In hindsight,” he said, “it sounds like something a preacher would say in a Southern Baptist church on a Sunday morning. ‘If you can look the other way because you think the economy’s doing better, you can ignore the fact that this man is obviously not a Christian, then you’re not behaving in a way that Jesus would have behaved.’

“So I meant that, and I still mean it. The whole point of Christianity is to behave as Jesus would have behaved – and Jesus would not have voted for Donald Trump, no matter what his pay was going to do as a result of that.”

Isbell lives with his family in Nashville now – the Tennessee city which is an island of Democratic blue in a sea of Republican red. This month he is preparing for a six-night stand at the Ryman Auditorium, Nashville’s amazing old tabernacle, nicknamed the mother church of country music because it was home for decades to the Grand Ole Opry’s Saturday night radio show.

He’ll be on stage there with the midterms less than two weeks away. Will he be overtly political with the election so close?

“Well, my job is to write songs and if I feel like it is an emergency and I feel like I need to say something political between the songs, then I’ll do that. But normally, if it doesn’t rhyme and it doesn’t involve me introducing my band, I’m not gonna say it, because I’m not a standup comedian, I’m not a lecturer and I don’t give Ted talks. If there’s not a melody and some rhyme there then you probably won’t hear it from me. But I think the songs speak enough.”