The aim of this paper is to examine the importance of the participation of Poland and Mexico, as medium sized countries, in institutions of the Atlantic Bridge, viewed from their perspective. We conduct an interdisciplinary study into relationships of regional and transregional integration groupings and defence alliances. We analyse the possible geopolitical and geo economic situation of Poland and Mexico in the event of weakening or disintegration of the EU, NAFTA, or NATO. We present two extreme scenarios as possible results of Brexit and the electoral victory of Donald Trump. According to the first scenario, the EU and NAFTA will not survive. For Poland and Mexico this would mean a lack of external support for reforms and of the barriers protectingthem from disintegration of their democratic states and liberal values. In the second scenario, both Brexit and Trumpism are seen as only turbulences, after which the systems will regain their stability. In this scenario, there would be a further decrease in the developmental differences between Poland and Mexico on one hand, and the EU and NAFTA on the other.
