The hopes of the French Revolution were most keenly felt by their Catholic coreligionists in Ireland. Using revolutionary universalism to surmount long-standing religious differences, the United Irishmen were founded in 1791 to create a new political network for substantive reforms. The network faced suppression after the 1793 Declaration of War, however, and reorganized into militant underground militia cells. Seeking aid from the French government for a militant uprising, the United Irish ultimately rose with disastrous results in 1798.

The American War led to still-greater agitation in Ireland, where a national movement arose seeking self-government and reform of the Irish Parliament. Whereas the British Parliament for centuries had possessed the right to veto Irish legislation, the Volunteer militia movement beginning in 1778 mobilized – at first nominally against the threat of Franco-Spanish invasion but quickly turned its attention to agitating for legislative independence. The measure would be achieved by the war’s end, while the Volunteers also sought religious integration off their forces and the expansion of Irish suffrage.