We investigate whether and, if so, when and where a new European integration
dimension emerges in national party competition that complements the traditional
left/right-dimension in Europe. We develop a Bayesian Finite Mixture Factor Analysis
to estimate the probability for the latent one-dimensional traditional left/right
and two-dimensional inverted U-shaped configuration with anti-European parties
at the peripheries. Our empirical analysis combines expert and transformed manifesto
data, covering the period since World War II. The estimation reveals that the
probability for a one-dimensional configuration becomes on average less likely than
the probability for a two-dimensional configuration since the late 1980s. We provide
evidence that the increasing transfer of competences to the EU as manifested by EU
membership plays a key role for the emergence of the European integration dimension.
Our findings are supported by a series of validity tests and have implications
for a many political phenomena
