2003 Polish European Union membership referendum

joined the European Union that year following the ratification of the Treaty of Accession 2003. The country's first European Parliament elections

Law and Justice party was openly critical of the EU's social agenda but ultimately supported joining the EU on economic grounds. The radical agrarian Self-Defence of the Republic of Poland was strongly Eurosceptic since its foundation but ultimately stayed neutral during the campaign. The far-right League of Polish Families was the only party in the Sejm which supported the "No" campaign.^[2]