Worst crisis in US-German relations since World war two. Klaus Scharioth, Berlin’s former ambassador to the US, tells DW why Germany’s expulsion of the top CIA official was right and why the current crisis is the biggest challenge yet for transatlantic ties. Klaus Scharioth served as Germany’s ambassador to Washington from 2006 to 2011. He is currently dean of the Mercator College for International Affairs in Germany and professor of practice at Tuft University’s Fletcher School in the US. DW: Berlin’s decision to publicly ask the head of the CIA in Germany leave the country is unprecedented in German-American relations and has triggered a major debate. Was the move justified or overblown? I think it was a measured response. I believe there had to be a response because what happened is really an espionage overreach which you don’t have among friends. And therefore I believe the response was measured. With a steady drip of new revelations about possible US intelligence operations in Germany coming to light do you consider the current crisis the most serious for US-German relations so far? Yes I believe this is a very, very serious crisis. I believe there was no need to do that. If the United States wants to know what the Germans are thinking, what the people in the foreign ministry or in the chancellory are thinking they should just call. That’s very easy. I know from my days in Washington in office that we have such a close relationship that we talk practically about everything and we also don’t hesitate to talk about differences. So there is and was no reason for this kind of espionage. And therefore I think this was basically a waste of taxpayers’ money. And it also showed a certain lack of respect of the intelligence community in the United States versus Germany.