In the aftermath of Britain’s 2016 decision to leave the EU, the Irish-American ethnic lobby remobilized to defend the Belfast/Good Friday Agreement from the threats posed by Brexit.

Drawing on interviews in Washington, Belfast, Dublin and London, Cowell-Meyers and Gallaher explore how the lobby shaped US policy towards Brexit in order to prevent the reimposition of a hard border on the island of Ireland and preserve peace. The authors also consider the lobby’s approach to other contentious issues, including a united Ireland and Troubles-related investigations.

‘In the winding, rocky road of the UK’s negotiations to leave the EU, the United States made some critically important interventions. This fascinating book explains how and why these predominantly related to Brexit’s impact on the island of Ireland. More broadly, it testifies to the use of soft power, cultural affinity and personal commitment to effect change abroad – which may, of course, bring risks as well as rewards.'

Katy Hayward, Queens University Belfast

'To assess organized Irish America’s role in stopping the most inane and reckless follies in the Brexiteers’ ‘plans’ for Ireland, there are none better qualified than Professors Kimberly Cowell-Meyers and Carolyn Gallaher. Both scholars have extensive primary research experience in Northern Ireland. And both have decades of scholarly engagement in the diplomatic and party-political pentangle that links Belfast, Dublin, London, Brussels and Washington. The Green Wall is, and will remain, a must-read for those who want to know how Irish Americans helped prevent the resurrection of securitized border functions across the partition line in Ireland, not least by exposing unicorns wrapped in the Union Jack.' Brendan O’Leary, University of Pennsylvania

Kimberly Cowell-Meyers is Associate Professor in the Government Department at American University, Washington, D.C.

Carolyn Gallaher is Professor at the School of International Service at American University, Washington, D.C.