Form a government after the resignation Erhard
After the general election in 1965 the CDU, CSU and FDP had initially continued the coalition government under Chancellor Ludwig Erhard. A year later, however, the two parties came to a Koalitonskrise. The Union thereupon nominated on November 10, 1966 Kiesinger as a new candidate for chancellor. After the failure of renewed coalition negotiations with the FDP, a grand coalition was formed.
The SPD would have had a majority even with the FDP in the Bundestag. Parts of the FDP rejected this but. Therefore, they had concerns that the small majority would not be enough to choose Willy Brandt as chancellor in the SPD.