The history of Union Ireland is typically told through its best-known historical events and leaders - from the 1798 Rising, the Great Famine, and the Irish Revolution, to Parnell and De Valera -- and as moments of sectarian division and high parliamentary politics. Instead, Ciaran O'Neill here makes the case for a broader, more inclusive, and decentred approach that emphasizes transnational phenomena, a settler-colonial diaspora, and minority groups on the island. Through the lenses of 'power' and 'powerlessness', he demonstrates that the received historiographical wisdoms suffer from several misconceptions: on the one hand they misconstrue the nature of power and the powerful, perpetuating historical myths about the 'ungovernability' of Ireland. After securing the Union, the British state proceeded to govern Ireland with less and less certainty of ever persuading its citizens of its legitimacy. Despite all reforms and investment, there was a widespread sense that Ireland would never recover and be a willing partner in the Union. And on the other hand they take at face value the nature of the so-called 'powerless', ignoring the myriad ways in which marginalized and diasporic groups negotiated and asserted their agency during the Union period, influencing and transforming the powerful centre in the process. The result is an untraditional and thought-provoking reappraisal of Union Ireland that raises important questions about colonialism and resistance - of what it means to govern and be governed, and the long-lasting legacies of the spaces in between.