Abstract A growing number of governments are seeking to return control from supranational authorities to the state. Many of them wish to do so without sacrificing the benefits of deep international cooperation. But this desire to increase national control while maintaining cooperation – which we term ‘sovereigntist internationalism’ – is often frustrated in practice. We argue that this is due to a ‘trust paradox’ these governments face when their ideological commitments push them towards trust-based institutional arrangements while simultaneously rendering them less trusting and less trustworthy. We illustrate our argument with a case study of the Brexit negotiations during Theresa May’s premiership from 2016 to 2019. Drawing on elite interviews, we show how the UK government sought to transpose existing forms of economic cooperation into looser institutional arrangements but failed to convince the European Commission that enough trust could be generated to make the continuation of deep cooperation viable without strong control mechanisms. Our argument advances debates in International Relations (IR) by, first, explaining governments’ sometimes contradictory preferences for institutional designs; second, showing that different actors need different levels of trust to achieve similar levels of cooperation; and, third, improving our understanding of how populist actors view international institutions.
Martill et al. (2026) studied this question.