Prime Minister Kyriakos Mitsotakis has made his election-year calculation plain: either his conservatives win outright, or they turn to one party alone, the center-left PASOK, which has already said it wants nothing to do with them.
Under no circumstances, he said on Tuesday, would that include Alexis Tsipras.
"Are we serious?" Mr. Mitsotakis asked at a conference hosted by the Proto Thema media group, when asked about a possible deal with the former leftist prime minister.
"I rule it out categorically. First of all, he wants to put us all in prison."
The remarks offered the clearest picture yet of how Mr.Mitsotakis plans to fight the national elections expected next spring.
His New Democracy party has governed since 2019 and leads every poll, typically at around 29 to 31 percent.
That is comfortably ahead of Mr. Tsipras's new party, ELAS, and of PASOK, but well short of the share needed for a parliamentary majority.
Mr. Mitsotakis has ruled out allying with the smaller nationalist parties to his right.
That leaves PASOK, which held a party congress specifically to reject cooperation with him.
The prime minister turned that rebuff into an argument: if no one will govern with him, he suggested, voters should give him a majority.
"The second and third parties combined are below New Democracy," he said.
"After seven and a half years, that is not a bad position."
He also raised the stakes for himself.
Asked what he would do if his party fell below 25 percent, he said it would be a poor result and he "would not hesitate to take responsibility."
When his time as prime minister ends, he added, he will leave parliament too.
Mr. Mitsotakis named restoring Greece's standing abroad as his proudest achievement.
His greatest regret, he said, was moving too slowly on a fraud scandal at OPEKEPE, the state agency that pays farm subsidies.
Why seek a third term? Greece's future would be settled by 2030, he said, "whether it is among the winners or the losers," and he still has the energy for the job.
Asked what he missed most about ordinary life, he said waking up without dozens of decisions waiting.
He recalled that Barack Obama, asked the same question, joked that he would open a T-shirt shop in Hawaii selling only white shirts in size large, so he would never have to decide anything again.