International regime formation revisited: Explaining ratification behaviour with respect to long-range transboundary air pollution agreements in Europe

We draw on the policy diffusion literature to shed more light on the determinants of treaty ratification, a crucial step in the formation of international regimes. Our hypotheses stipulate that a country’s ratification behaviour is influenced by the ratification choices of other countries in general, or of specific types of other countries. The underlying argument is that the ratification behaviour of (specific) other countries sends particular signals — for instance signals about implementation costs, competitiveness effects or reputation costs — to the country in question. The empirical testing is done on data for ratification of the UN Economic Commission for Europe’s agreements on long-range transboundary air pollution. The results show that international factors are as important in influencing ratification choices as domestic factors. This result raises interesting questions about the relative importance of international and domestic determinants in different policy areas and at different stages of international regime formation.