WHAT would the world be like now if George W Bush read poetry? It's a thought that pops up in conversation with Tess Gallagher, soon to appear at the Wigtown literary festival. Gallagher, one of America's leading authors of short stories and poetry and widow of Raymond Carver, writes in her new collection, Dear Ghosts, that "once we feel deeply we begin to behave". It is her contention that poetry leads readers to enlarge their feelings. She considers the image of Bush transformed by a slim volume. "You'd like to think so. Poetry does change people and that's why I write it. I love fiction, but poetry is the real way."

Gallagher is nothing if not proof that poetry can transform a life. Her alcoholic father beat her; her brother died in a car accident at the age of 15; her second husband was an alcoholic; and her third, Carver, died young of lung cancer. Yet I don't think I've ever spoken to another interviewee who has laughed so much or been so open.

Earlier this year, Bloodaxe published Dear Ghosts, her first collection of poetry in 14 years, during which time Gallagher was taking care of her mother, who had Alzheimer's, and was fighting breast cancer.

"It was very important to be with my mother during that last part of her life. It was very strenuous but very rewarding. There aren't many people who take on 24-hour care of your parents. I was doing that while I was doing chemo. It was the sick taking care of the sick." She's been in the clear for five years.

Bush comes up when we talk about the lines in Dear Ghosts, which remembers her first husband, a pilot during the Vietnam war. The marriage didn't long survive his return from the conflict. As she writes in I Have Never Wanted To March, she can't quite believe her country hasn't learned the lessons of the earlier war.

"I protested the Patriot Act. The artist Alfredo Arreguin, who did the cover of Dear Ghosts, did a portrait of me with the American flag behind me and the text of I Have Never Wanted To March written across my face. We blew it up and put it on the front of my house because all around my neighbourhood everyone had the American flag up. They had a different notion of what a patriot was. The way my poems were moving I felt like, according to the Patriot Act, I wasn't a patriot, because I disagreed with the war."

Gallagher's neighbourhood is in Port Angeles, a three-hour car and ferry journey from Seattle. It's her childhood home, and she describes it as the most beautiful place on Earth. She grew up in the forests, in the clearances where her father and mother worked as loggers. Your mother too? I ask. "Yes, she worked right along side my dad - one of the few women who did that. It was very physical, demanding work, very dangerous. I never thought women were just creatures of the kitchen. She was an adventurer, she could fix anything."

After high school, she enrolled at the University of Washington and studied poetry under Theodore Roethke. Gallagher later taught poetry, though she has largely retired from that now. Perhaps her last pupil is Josie Gray, her current partner, an Irish painter and storyteller. Gallagher has visited Ireland, specifically Ballindoon in Sligo, practically every year since 1968, when she first went on a pilgrimage to Yeats's grave. This month sees the publication of Barnacle Soup, a book co-authored by the couple. Essentially, it is a collection of shaggy dog tales that Gray collected and Gallagher transmitted to prose.

"He began to tell me these stories and I just loved them. I decided to tape record them because when Josie is off the planet, these stories just won't exist any more. I thought it would be a lovely thing to do for a part of the country I've loved so long."

Barnacle Soup is not the first time Gallagher has worked with a partner. "When I was working with Ray, he would say, Suggest something there. You don't think it works, what would you do?' And I would try to do it in his key." Gallagher lived with Carver from 1979 until his death at the age of 50 in 1988; they married six weeks before he died.

"He encouraged me. I thought writing a story would be like writing a poem, each line more or less perfected as the poem was happening. In fiction though, you have to move very quickly, and Ray told me not to take my pen off the paper. Just to get that story down no matter how roughly because you're going to rewrite it. That was a great help for me as it took me to a certain velocity needed to get the work down."

I ask if she minds being asked about Carver; every interviewer mentions him and it would only be human if she resented it. She says not at all: "Just so long as it's clear that my life has moved on, that it hasn't been mothballed. I did get a strange piece written about me in the Irish Times that subdued me to the Carver legend. I've now lived 20 years past Ray's death, and he's an important part of my life and I think about him every day and still love him, but the heart is very large and I have my own work."

After the sacrifices she's made, emotional and financial, as an author, would she recommend the writing life to a young would-be author?

"I have a nephew now who has taken up writing. I love it, having something to pass on. There were times when I didn't have a telephone, didn't have a car. Not even a very good typewriter ribbon. I was working several jobs, putting myself through college - so yeah a lot of sacrifices, but it's been worth it."

Tess Gallagher appears with Josie Gray at the Wigtown Book Festival on September 28, 7pm Barnacle Soup (Blackstaff Books, £11,99) Dear Ghosts, (Bloodaxe, £8.95)