Following the partition of Ireland and establishment of the Irish Free State, Irish-American interest in Irish nationalism significantly decreased. Irish neutrality in the Second World War and increased Irish-American assimilation further diminished levels of participation in nationalist organizations. The United States government itself pursued a policy of non-intervention in Northern Irish affairs for decades. Nevertheless, American interest in Ireland and Irish culture persisted and left the potential for future political mobilization on Irish issues.

The United States government faced a turning point in its Northern Irish policy in the 1970s, as the Troubles and internment sparked Irish-American protests. Irish-American organizations such as the Irish Northern Aid Committee (Noraid), founded in 1970, raised funds for the republican movement and were accused of fostering close ties with the Provisional IRA. By 1977, British security forces claimed that almost 80 per cent of IRA weapons came from the United States. Other Irish-American organizations worked to lobby the American government. The congressional organization, Friends of Ireland (FOI), founded in 1981, included influential senators Ted Kennedy and Daniel Moynihan, Speaker of the House Tip O'Neill, and New York Governor Hugh Carey. FOI combated IRA fundraising and pressured the United States government to end its non-intervention policy. The organization lobbied for a statement on Northern Ireland from Jimmy Carter, who took a special interest in the Troubles because of his human rights agenda. On 30 August 1977, Carter condemned violence and promised American aid and investment if a peaceful settlement was achieved.

During Ronald Reagan's administration, FOI maintained pressure on the Irish question, which, when combined with other elements, helped lead to action. Reagan continued American involvement in Northern Ireland, actively encouraging compromise during the negotiations that produced the 1985 Anglo-Irish Agreement. Many Ulster unionists were hostile to the 1985 agreement and suspicious of American involvement in the peace process. They felt isolated by the perceived pro-republican stances of the United States. Unionists attacked American government involvement, and condemned Noraid and other American organizations for supporting the IRA. Focused on opposition to Irish republicans, unionists did little to present their own vision of Northern Irish society to Americans.