He previously was a visiting researcher at Berkeley, Stanford, Hastings Law School and Bilgi University, Istanbul, as well as a visiting fellow at the European Political Strategy Centre (EPSC) the in-house think tank of Commission President Juncker. Armin regularly provides legal advice to public and private parties on different fields of EU law. His research largely focusses on EU constitutional law and theory, sovereignty, Brexit, (con)federalism and the euro, often in a comparative perspective. He has been published in several leading international journals, including the Common Market Law Review, the European Law Journal and the European Constitutional Law Review.