This paper examines the Twitter social graph of German politicians and political parties during a time period not potentially biased by nearby elections. Based on a data set of 1,719 politicians across the entire political spectrum of this important country in the EU, two graphs are constructed, which also reflect relationships within and between parties: the follower graph, consisting of all follower-followee relationships between German politicians, and the “mention graph”, which models direct references of politicians to their colleagues. Our main contributions are as follows: First, we analyse these graphs according to several statistics and graph metrics, characterizing political parties according to their collective participation in Twit-ter. We also investigate the openness for following ideas across political camps, resulting in the dis-covery of three distinct groups of political parties. We also find that membership in political parties itself explains only little of the variation in the formation of ties. There is also evidence that politicians with less activity exhibit a higher degree of openness than users with active engagement in tweets and discussions. This case study on social media adoption in politics leads to interesting insights into po-litical debate in the information society.