Leading members of Germany's Social Democrats (SPD) spoke out for a three-way left wing alliance as an alternative to their fragile 'grand coalition' with Chancellor Angela Merkel's conservatives at the weekend.
Turmoil within the SPD has cast doubt over the future of the government in Europe's biggest economy after the party chief quit due to dismal regional and European election results.
Calls are mounting from members to ditch the coalition later this year and shift left, a move that would hasten Merkel's exit and could lead to a snap election, a minority government or an unwieldy three-way alliance.
Some of the SPD's most senior figures homed in on a tie-up with the resurgent Greens, who have even overtaken the conservatives in some opinion polls, and the radical Left, a successor party to East Germany's Communists.
Deputy SPD leader Ralf Stegner told the Frankfurter Allgemeine Sonntagszeitung that "of course" a leftist alliance was "the strategic alternative to one with the conservatives."
Malu Dreyer, one of three caretaker leaders of the SPD, also raised the possibility.
"We need other constellations to boost our credibility. One option is of course a coalition of the SPD, Greens and Left," she told Saturday's Sueddeutsche Zeitung newspaper.
Their comments add weight to a chorus from the party's left for such a three-way alliance which has never been tested at the national level but is working in two federal states.
One of Europe's biggest centre-left parties, the SPD alternated power with the conservatives for generations but taking on the role of junior partner under Merkel for two straight terms has led to a slump in polls.
In a European election on May 26, the SPD was pushed into third with just 15.8% of the vote, down some 11 points and behind the Greens for the first time ever in a national election. Since then, it has slumped to 12% in opinion polls.
The three parties are also trying to forge a leftist coalition in the state of Bremen although the conservative Christian Democrats (CDU) won most votes in a May vote there. This has sent a signal to the CDU that they cannot bank on keeping power by coming first in elections.
Merkel protege and CDU chief Annegret Kramp-Karrenbauer was cool on the idea of cooperating with the Greens, defying some in her party.
"Anyone who dreams of a new government and votes Green must know they can wake up with the Left party," she told Bild am Sonntag. "Bremen shows: if in doubt, the Greens don't go for conservative policies but to the left."
