SPD party members still smarting over his decision to renew the loveless "grand coalition" despite initially pledging to take the SPD into opposition. "For that reason, I declare that I won't enter into the federal government - and at the same time sincerely hope to put an end to the personnel debate within the SPD".
German Chancellor Angela Merkel's hoped-for fourth government suffered a first defeat Friday before even being sworn in, as prospective foreign minister Martin Schulz stepped back after a series of U-turns. Many of them are skeptical after the party's disastrous election result, which followed four years of a "grand coalition" with the party serving as junior partner to Merkel's conservatives.
The SPD, Christian Democratic Union (CDU) and the Christian Social Union reached the coalition deal on Wednesday, which will possibly end the new government vacuum since the September 24 federal election, the longest period ever since 1949.
He is not the only one feeling let down by the results of party leaders' days-long negotiating marathon earlier this week.
SPD leader Martin Schulz drew strong criticism in the party after he announced on Wednesday that he would resign as SPD chairman to become foreign minister, after promising before the election that he would not serve in a Merkel-led government.
After the SPD's losses in the September 24 national election, Schulz announced that the SPD would go into coalition and that he wouldn't hold talks with Merkel. Schulz had suggested his successor should be parliamentary group chief Andrea Nahles, according to German media.
Another party official told a Bild: "The party is deteriorating".
Asked if Sigmar Gabriel would remain foreign minister, she said party leaders would soon decide on a way forward, but their primary focus now was securing a "yes" vote from rank and file.
For the SPD, the backbiting went public when Gabriel, Germany's acting foreign minister, attacked the leadership for planning to remove him from his post - and implying that he'd been promised that he could continue as the country's top diplomat.
Any agreement will be submitted to a ballot of the Social Democrats' members, a process that will take a few weeks.