Germany’s Social Democrats (SPD) punched above their weight and won. They have secured three key ministries in negotiations for another coalition government with the right: finance, foreign affairs and labor. For a party with only 20 percent support, that is an impressive result.

Yet they are in trouble.

After the election in September, SPD leader Martin Schulz ruled out another “grand coalition” with the conservatives. He ruled out personally joining another government led by Angela Merkel. Now another grand coalition is in the making and Schulz will most likely become its foreign minister.

The damage of this U-turn should not be underestimated. Schulz has lost his credibility and his reputation. A campaign is underway inside the SPD, led by its youth wing, to block another grand coalition. (Party members must approve the deal before it can go through.)

Given the fate of its sister parties in Europe, the SPD should have been aware of the dangers of putting personal ambitions over party politics.