Throughout the first two decades of the twentieth century, Irish unionists feared the influence of Irish-America on the nationalist movement. Even as nationalism in both Ireland and America was recovering from divisions following the end of the Parnell era, Irish-America was seen as pushing the nationalist movement toward extremism and separatism through the power of finances. As expressed by James Campbell, MP for Dublin University, the influence of Irish-America was an important factor in the unionists’ reluctance to accept even limited forms of devolution for Ireland. Unionists believed such measures would open the door for separatists and extremists to sweep in against the wishes of the majority of Irish people and force the establishment of an independent nation.

At the same time, the decline of landed power and greater democratic involvement meant Irish unionism was becoming increasingly focused on localities. Southern unionism weakened significantly due to changes in landlord-tenant relations, dismantling of economic positions, and decreased political power. As southern unionist identities diverged from those of Ulster, those in the south felt pressed to rely on Irish unionists sitting in English constituencies to represent their interests, rather than MPs from the north of Ireland. Over time, unionists in Ulster focused on a distinctive Ulster unionist identity separate from the rest of Irish unionism. Landlords who had once led the unionist movement in both the north and south now gave way to an increasingly populist leadership. Many unionists believed constructive policies at the turn of the century had addressed the grievances of the Irish people, thus forcing Irish nationalists to turn to Irish-America for support and funding. During the third Home Rule crisis, unionists portrayed Irish nationalists as unrepresentative of the Irish people because of the influence of their American paymasters.