WHAT IS an Irish novel? The question hovers over literary history - Is Elizabeth Bowen Irish? What about Iris Murdoch? - and will never be answered definitively. But it arises in a different way from usual when we come to the celebrations in the US of the 75th anniversary of the publication of the biggest-selling American novel of all time, Margaret Mitchell’s Gone with the Wind.

No one would claim that Mitchell’s blockbuster is anything other than American and Southern. The issues with which it is entwined - the American Civil War, the Old South, race, versions of femininity - are very obvious and specific.

But there is a case for looking at it through another lens: as the most exotic fruit of Irish diaspora literature.

For those who have seen the film but not read the book, it is not obvious that there is much that is Irish in it beyond the name of the heroine, Scarlett O’Hara, and of the plantation on which she grows up, Tara. David Selznick, who made the movie, was drawn towards a nostalgic, simplified version of Old South aristocracy and flattened out Mitchell’s much more complex picture of ethnic and economic diversity in the white South.

The novel is far more deeply Irish than the movie. Scarlett’s father, Gerald, has “the brogue of County Meath still heavy on his tongue in spite of thirty-nine years in America”, and that Irish brogue is heavy on Mitchell’s tongue, too. Mitchell’s identification with the Irish part of her ancestry was deliberate. Like many Americans, she had a diverse ancestry, with strong roots in Huguenot France and in Scotland. She could have chosen either of these bloodlines. Instead she identified most with the Irish strain in her ancestry.

Scarlett is essentially a version of Mitchell’s maternal grandmother, Annie Fitzgerald Stephens. Annie and Scarlett are the same age, are born in the same place, come from virtually all-female families, move to Atlanta but remain obsessed with the old plantation. While the sexual melodramas of Scarlett’s life are inventions, her headstrong wilful nature and grasping, ruthless pursuit of material wealth are closely based on Annie.

Annie was self-consciously Irish. The Stephens bit in her name came from her husband, John Stephens, who was born to an old Catholic gentry family in Birr, Co Offaly, established himself as a merchant in Atlanta and served six terms on the Atlanta police commission.

Mitchell’s great-grandfather Philip Fitzgerald was the kind of Irishman that we like to forget. He was an Irish Catholic emigrant from Tipperary. He and his family left Ireland shortly after the 1798 Rising, and they can be seen as Catholic refugees from oppression. But he was also a rich member of the Southern slave-owning class, with a plantation of almost 1,000 hectares in Jonesboro, near Atlanta, and 35 slaves. Fitzgerald epitomised a strain of Irish Catholic history that is uncomfortably ambiguous: oppressed in one context, oppressor in another.

Mitchell lived with Annie Fitzgerald Stephens as a child, and spent summers at the old plantation with her spinster Fitzgerald aunts. But there was more to her use of Irishness than that. The Irish strain in Mitchell’s make-up that went into the making of Gone with the Wind  was both literary and political.

It is not accidental that the title of Gone with the Wind  derives, via Ernest Dowson’s Cynara, from James Clarence Mangan: “Solomon! Where is thy throne? It is gone in the wind.” Mitchell was steeped in romantic 19th-century Irish literature. According to Mitchell’s biographer Darden Asbury Pyron, her mother, May Belle, “especially delighted in Irish balladeers like Thomas Moore. Considering herself thoroughly Irish, May Belle repeated how she shared ‘the story of Robert Emmet, of Tara, of the Bards’ with her schoolmates ... She could not control her enthusiasm over ‘my Father’s and my Grandfather’s country - the country of a Burke, a Curran, and of an Emmett’.”

Shortly after the publication of Gone with the Wind, Mitchell wrote to Michael McWhite of the Irish legation in Washington DC, thanking him for a copy of Mangan’s poems. She confessed to never having read them but went on to say something more significant: “I knew Dark Rosaleen, The Lament of Fitzgerald, The Ode to the Maguire, and others. The truth is I heard these poems orally and never had a copy of Mangan’s work in my hands.”

Mangan and Moore were more than literary influences for Mitchell: they were stitched into family lore. What they provided for her novel are the romance of defeat. Oppressed but defiant Ireland becomes the oppressed but defiant lost cause of the South. The dirty struggle for slavery is dignified with the nobility of Irish romanticism.

The political usefulness of Irishness for Mitchell is even more significant for the creation of Gone with the Wind  than this literary heritage. Irishness is a way of distancing the novel’s image of the South from the guilt of slavery. The Irish are not oppressors: they are the oppressed. They are not feudal aristocrats but hard-working frontier folk. Tara has not been granted to an effete English grandee - it has been carved out of nothing: “Tara’s bloom was not the work of a planter aristocrat, but of the plodding tireless ‘small farmer’ who loved his land.”

Gerald O’Hara is no planter lord but a classic immigrant capitalist, impatient of learning and greedy for practical advantage. It is remarked of him that he never felt his lack of education: “What need had he of these things in a new country where the most ignorant of bogtrotters had made great fortunes? In this country which asked only that a man be strong and unafraid of work?” In this passage Mitchell strategically embraces the usual insult against the Irish: ignorant bogtrotters. Why? Because the rise of an ignorant bogtrotter to slave owner cannot be due to racial privilege and oppression.

It is simply a perfect example of the opportunity the US affords the immigrant “unafraid of work”. Astonishingly, slave labour in the fields does not appear in the novel at all: we don’t read of blacks working in the field until the late post-emancipation scenes. Irish immigrant work functions to make black work disappear.

And for all its racism and all its evasiveness about the Old South, it is this Irish strain that gives Gone with the Wind  its compelling seam of truth. Scarlett’s insatiable, unrelenting drive to escape poverty and get rich is essentially the immigrant story. In a certain light Scarlett O’Hara is literature’s first great Irish capitalist.