Court actions over a possible breach of the Danish Constitution by the Maastricht Treaty as well as other EU-related constitutional cases before the German federal constitutional court in Karlsruhe and the Irish courts in relation to the Single European Act in 1987, the Crotty case.
In 2008-9 there were constitutional court cases challenging the ratification of the Lisbon Treaty in the United Kingdom, Slovakia, Germany, France and Denmark.
30 June 2009 the German Constitutional Court in Karlsruhe approved the Lisbon Treaty with strong conditions. See German Constitutional Court case.
3 November 2009 the Czech Constitutional Court approved the Lisbon Treaty permitting President Vaclav Klaus to sign it and thereby leading to its final ratification.
Danish Constitution and the EU