"You don't call a book Fourth of July anything without some intent to say something about America, or the American experience," says Henderson.

"I wanted to play with these notions of an intersection between freedom and community and where that happens in our country.

"America shifted after the election of Ronald Reagan and I wanted to play with these problems and see what I could shake out."

Fourth of July Creek is set in the early 1980s – Reagan was elected president in 1981 – in rural Montana. His protagonist is Pete Snow, a social worker trying to save damaged families, including his own. When an 11-year-old boy, barely alive, stumbles into a school yard, Snow is cast out into the forest to find his father, Jeremiah, a paranoid, reclusive survivalist.

Henderson got to shake out a lot of worries through the character of Jeremiah.

"At the outset you just think he's crazy but I really wanted to invest his consciousness with a lot of legitimacy," he says.

"One of his preoccupations is economics and I defy anyone to explain the world's economic system in a coherent, brief way.

"And the degree to which we have surrendered our personal privacy … do you really believe your private communications are private anymore? We just let these things happen.

"At this point in history there's a lot to worry about, a real disconnect between what we're told and what we can control. There are larger forces out there controlling our destiny and that makes many people frightened for the future.

"I wanted to write a character who was saying no to those things, and maybe that doesn't make him crazy but it makes him courageous."

Henderson grew up in rural Montana, "in my father's logging truck". His mother died of lung disease when he was 19, leaving him enough money to afford college, the first person in his immediate family to do so. He knew he wanted to be a writer but wasn't quite sure how to go about it, so he majored in Latin and Greek at the University of Montana "purely for the discipline".

"I was a little different, growing up among cowboys and loggers, I was always interested in books but I had a few teachers who said it was something I could do if I put my mind to it."

His first paying job out of college was at a group home for juveniles, working with children who had been through "every dark thing you could imagine", but he was soon drawn back to writing, working in corporate communications and as an advertising copywriter, working on his fiction in his spare time.

In 2012, he co-wrote a Chrysler advertisement, "Halftime in America", that starred Clint Eastwood and aired during the Superbowl, drawing an audience of more than 111 million viewers. The ad caused quite a stir, as it touched on the idea of a failing nation and how Americans needed to pull together to work out how to come from behind, how the nation's second half was about to begin.

But for Henderson it was all about telling a story, all he has ever wanted to do.

He began writing Fourth of July Creek about a decade ago. Initially it was two different stories, the social worker's and the survivalist's.

"I was working on them as two books, hedging my bets as I knew one of them was bound to be garbage, and both of them had the same problem, nothing was happening.

"And then it hit me, the characters had to meet, and almost instantly it felt as though that's where the story was headed all that time, that I had always been working to get them together."

Fourth of July Creek, by Smith Henderson. William Heinemann, $32.99.