Germany may be forced to delay ratification of the European Union's Lisbon reform treaty until after September's federal election due to demands from Chancellor Angela Merkel's conservative sister party in Bavaria, according to Reuters. The party's new proposals could be a blow for the treaty, which aims to give the 27-member bloc stronger leadership, more effective foreign policy and fairer decision-making, as they go beyond legal changes demanded by Germany's top court this week. "The Christian Social Union (CSU) wants to strengthen the influence of the Constitutional Court and the Bundestag (lower house of parliament) and give more explicit protection than previously planned," said a spokesman for the parliamentary party. On Tuesday, Germany's Constitutional Court ruled the Lisbon treaty was broadly compatible with national law, but demanded tweaks to domestic legislation before the treaty could be formally ratified. Merkel had said she expected the changes to be passed before Sept. 27's election and the ruling had appeared to remove one of several remaining hurdles for the treaty. But the CSU, part of Merkel's coalition with the Social Democrats, has taken a tougher line than the court which said an appendix to the German treaty law needed to make clear the Berlin parliament had a role in shaping Brussels' decisions. The CSU spokesman said his party wanted to anchor greater rights for the Bundestag and Bundesrat upper house in Germany's constitution. The party wanted the Berlin parliament to be able to take part in government decisions on EU matters, he said, which would mean changes to three articles in the constitution.