Political trust as a conditional relationship between citizens and institutions is essential for the stability of political systems. Although the EU-Institutions are extending increasingly their competences (Tallberg, 2002), trust in them is mostly determined by national trust (Harteveld et al., 2013). Two theories, how national trust spills over to the EU-Level, are introduced: The congruence theory (Anderson, 1998) assumes a positive relation on the individual level based on proxy-theory and the compensation theory (Sánchez-Cuenca, 2000) postulates a negative one, applying a cost-benefit approach. To combine both theories, the latter was shifted to the aggregated level of EU-member-states (Muñoz et al., 2011). With the help of the ESS Round 9 (2018), both theories are analyzed comprehensively. The findings clearly confirm the existence of a congruence effect to explain variation inside a country. Between EU-member-states differences can be partly explained by the compensation theory, but the results are less robust.
