According to author and amateur historian Tom Mahon, "There were many contradictions and weaknesses in O'Donnell's polemic. In reality, the IRA was a "petit bourgeoisie" conspiratorial organisation rather than a workers' and peasants' army. It was firmly rooted in the nineteenth-century concept of a nationalist revolution and its few socialists were largely peripheral to the organisation. Kevin O'Higgins, a leading Sinn Féin activist during the Anglo-Irish War, famously said, 'We were probably the most conservative-minded revolutionaries who ever put through a successful revolution.' Additionally, O'Donnell failed to justify the IRA's refusal to acknowledge the wishes of the majority of the southern Irish population who supported the Free State. Most glaring of all, he had no satisfactory explanation of what to do with the Protestant working-class in Northern Ireland, who were prepared to take up arms to prevent their 'liberation' by the IRA. Despite the many flaws of his argument, he has received much serious attention from historians and biographers."