Outgoing prime minister Alexis Tsipras said on Thursday he would not form a coalition government with any of Greece’s establishment parties after snap elections next month.

“I’m not going to be prime minister [if it means] cooperating with parties from the old political system,” he said in a television interview.

But it is difficult to see how the far-left leader could stay in power if he rules out deals with the centrist To Potami or PASOK, Greece’s once-dominant social democrat party.

Tsipras’ Syriza currently rules in coalition with the right-wing Independent Greeks, an ideologically fraught alliance that is only sustained by a shared animosity toward the country’s European creditors.

Since Tsipras reneged on his January election promises to cancel austerity, the rationale for that alliance would appear to have gone away.

In July – following months of strenuous negotiations — the Greek leader agreed to enact far-reaching economic and political reforms to win a third, €86 billion bailout from the European Union.

Greece desperately needed the money to contain a bank run and stave off sovereign default which could have triggered its ejection from the eurozone.

Tsipras’ capitulation divided Syriza. Dozens of his 149 members refused to back the bailout plan in parliament, forcing the prime minister to rely on the very “establishment” parties he disparaged on Thursday to get it approved.

Last week, 25 of Syriza’s lawmakers walked out to form a new anti-bailout party, Popular Unity. It could conceivably form a coalition with Syriza after next month’s election but then what was the point of splitting away?

Polls show Tsipras remains personally popular but there’s little chance the rump Syriza will win enough support for an absolute majority. It only got 30 percent of the votes in January.

No opinion poll has been published since Tsipras called snap elections but earlier surveys gave the unified Syriza around 33 percent support, not enough for a majority. Assuming Popular Unity takes several percentage points off that, the chances of Tsipras being able to govern without To Potami or PASOK seem remote.