Our seminar will offer the opportunity to present and discuss the results of an extensive study, covering the determinants of internal policy which govern Poland's involvement in cooperation in the EU - or in contesting EU activities and values. It will be the first presentation of this report outside of Poland. A research team from Adam Mickiewicz University (Poznań, Poland) reconstructed the goals of Polish European Policy (2004 - 2018) and sought to identify and demonstrate how these goals have been understood by subsequent governments over the years. This team also assessed Polish influence on the decision-making process within the European Union during the analysed period, indicating the determinants of successes and failures in these matters. Researchers also analysed Polish European Policy 2004 – 2018, in the context of EU-related activity of the Union’s largest member states and countries from the Visegrad Group.