Multifaceted in its character, the relationship between Poland and the European Union is now more than a quarter of a century old. After the breakdown of the Eastern bloc, Poland signed the Association Agreement with the then European Communities in December 1991, which led up to an EU membership application three years later. Not yet a member, the country had some impact on the Union in the Nice Treaty negotiations (2000–2001), as well as on the European Constitutional Convention proceedings (2001–2003). After a successful EU membership referendum in 2003, reflecting a great deal of societal support, Poland, along with nine other newcomers, became a fully-fledged member of the EU. Once within the bloc, Warsaw was at pains to develop a more coherent EU policy, as it often changed its positions between more collaborative approaches and veto threats, but also absolving a successful rotating EU Council presidency in 2011. The country collaborated with other member states in Central and Eastern Europe—in the Visegrád framework and with the older member states—through the Weimar Triangle, for example, however with sometimes mixed results. Poland has prioritized a number of issues in the EU such as the energy sector, security and defense, and the Eastern partnership, the latter focusing on the EU Eastern neighbors, including Ukraine and Belarus. In particular, during the Ukraine-Russia conflict of 2014–2015, Poland was one of most active actors in the EU foreign policy. However, since 2015 Poland has become a subject of controversy within the EU, regarding the rule of law standards that were criticized by the European Commission and Warsaw’s rejection of a relocation scheme in the EU refugee and migrant policy.