2005-2017: Angela Merkel (CDU)
2005: Gerhard Schröder (SPD), Guido Westerwelle (FDP), Gregor Gysi & Oskar Lafontaine (Left), Joschka Fischer (Green)
2009: Frank-Walter Steinmeier (SPD), Guido Westerwelle (FDP), Gregor Gysi & Oskar Lafontaine (Left), Jürgen Trittin & Renate Künast (Green)
2013: Peer Steinbrück (SPD), Gregor Gysi (Left), Jürgen Trittin & Katrin Göring-Eckardt (Green)
2017-2020: Martin Schulz (SPD)
2017: Ursula von der Leyen (CDU-CSU), Frauke Petry (AfD), Christian Lindner (FDP), Dietmar Bartsch & Sahra Wagenknecht (Left), Robert Habeck (Green)
2020-: Cem Özdemir (Green)
2020: Markus Söder (CSU-CDU), Martin Schulz (SPD), Beatrix von Storch (AfD), Christian Linder (FDP), Hubert Aiwanger (Free Voters)
At the end of 2016, not long after congratulating Hillary Clinton on her historic victory, Angela Merkel announced that she would not lead her party into next year's election and would instead retire. Early in 2017 Defence Minister Ursula von der Leyen was selected as her successor as CDU leader and was shortly afterwards confirmed as the CDU-CSU's Kanzlerkandidat, facing a surprisingly competitive challenge from Friedrich Merz. That near-loss in an internal election foreshadowed what was to come. Von der Leyen soon proved to be gaffe-prone and indecisive, drawing the ire of the right and alienating moderates with her half-hearted and cynical criticisms of her government's handling of the million migrants accepted into Germany. This left the 2017 election surprisingly volatile and it soon became clear that the SPD's hail-mary pass in the form of Martin Schulz was paying off. The SPD was tied with the CDU for most of the election, but few truly believed that the SPD could win the election until the exit poll.
The post-election negotiations proved extremely painful. Both Schulz and Von der Leyen had ruled out another grand coalition during the election campaign but after Christian Linder blew up negotiations for a "Traffic Light" coalition, there was little alternative. It was not until December that a new coalition could be formed, one that was barely approved by the membership of either party and cost Von der Leyen her career.
The Schulz government soon proved to be deeply unstable. The CDU bristled constantly as the junior partner in the coalition and there were constant disputes over everything from immigration to integration. Any and every domestic achievement, from the minimum wage to same-sex marriage, was a long, brutal, drawn-out negotiation that left all sides feeling disappointed. Chancellor Schulz was no more effective on the international stage: he became a roadblock for President Clinton's efforts to create an anti-Putin alliance, François Fillon emerged as the leading European statesperson in Merkel's absence and his remarks on European integration were a large contributor to David Cameron's downfall in early 2018. As both governing parties slipped steadily in the polls their differences came to a head in early 2020. The CDU, unable to tolerate its subordinate position in the government, presented an ultimatum to Schulz calling for a much tougher line on refugees and what they were entitled to from the German state. Schulz called their bluff, and the government collapsed.
In a hail-mary pass of their own the CDU nominated Bavarian Minister-President and constant Schulz critic Markus Söder as their Kanzlerkandidat, but he was soon bogged down by gaffes and corruption controversies of his own. Instead the party that had led the polls for the previous two years continued to lead in the polls. Despite everything no-one seemed to truly believe that Ozdemir could become the first Green Chancellor until election night, where the Greens got their best ever result and the SPD their worst ever one. It took another four painstaking months for a coalition to be formed, with Linder frequently threatening to collapse the negotiations just like four years earlier. While the rise of the Greens and Ozdemir had boosted the CDU and the AfD in the polls - for the wrong reasons - the former party of government has been embroiled in infighting over it's ideological direction and potential co-operation with parties to their right. And the current government is proving to be only slightly more stable than it's predecessor.