Trittin, at the time co-chairman of the Green Party’s parliamentary group, to become minister of finance in the case of his win. Although Steinbrück soon won the endorsement of former Chancellors Gerhard Schröder and Helmut Schmidt, his gaffe-prone campaign never gained traction against the popular Merkel. His previously established reputation as a crisis manager who had played a frontline role in fighting the global financial crisis was overshadowed by faux pas throughout the campaign. He clashed with Sigmar Gabriel, the party leader, whom Steinbrück said had not been supportive of his campaign. On 22 September, Steinbrück's Social Democrats won 25.7 percent, while Merkel's CDU and its Bavarian sister party CSU together won 41.5 percent of the vote. Following the elections, Steinbrück was part of the SPD delegation to hold exploratory talks with the CDU/CSU on forming a coalition government. Member of the Bundestag, 2013–2016 As member of parliament, Steinbrück served on the Committee on Foreign Affairs and as chairman of the German-American Parliamentary Friendship Group from 2013 until 2016. In March 2015, Steinbrück joined the Agency for Modernization of Ukraine, an initiative led by Dmitry Firtash to develop a comprehensive plan of political and economic reforms in the country. In September 2015, Steinbrück announced that he would not stand in the 2017 federal elections. He vacated his Bundestag seat in the end of September 2016. In 2018, he wrote a book titled Das Elend der Sozial-demokratie. Anmerkungen eines Genossen., which explored the reasons why the SPD always lost elections from an insider's perspective. Political positions Economic policy Steinbrück has been a prominent speaker for the SPD, especially on economic matters. During a 2007 visit to Washington for meetings with the Treasury secretary, Henry M. Paulson Jr. and Ben S. Bernanke, chairman of the Federal Reserve, after the collapse of Amaranth Advisors, Steinbrück lobbied for the development of an internationally accepted "code of conduct" for the hedge fund industry, arguing that a "sizable number" of hedge funds "are not behaving properly." Steinbrück predicted in 2008, in the wake of Lehman Brothers’s bankruptcy, that the United States’ days as a financial superpower were numbered. In December 2008 interview with Newsweek, he controversially attacked the British Keynesian approach to economic policy. He raised scepticism about the effectiveness of large fiscal stimulus packages and criticized the resulting increase in public debt. His comments led Steinbrück into a highly public press battle with Paul Krugman,