Tsipras, 51, said at a public event launching his Greek Left Alliance that “the aim is not only political change, but policy change”, calling for “a major democratic and social overhaul of the country”.
Greece, he said, “needs a shock of integrity and democracy”.
Tsipras was Greece’s leftist prime minister at the close of the country’s decade-long economic crisis.
The former radical Communist came to power in 2015 promising to eliminate austerity. He clashed with Greece’s EU-IMF creditors, almost crashing the country out of the euro.
He ultimately backed down and signed a final rescue deal that enabled Greece to exit the crisis in 2018.
The compromise split Tsipras’s Syriza party, which went on to lose successive elections to the conservative New Democracy party of Kyriakos Mitsotakis.
Tsipras stepped down as Syriza leader in 2023 after another defeat, and later resigned as a member of parliament in October.
Greece’s next legislative elections are scheduled for 2027, but there is speculation they could be held as early as September to enable Mitsotakis to catch opponents unprepared.
Opinion polls have shown that up to 18% of respondents could back a party headed by Tsipras, who is expected to poach several Syriza MPs and cadres, potentially enough for second place.
Government dogged by scandals
Mounting prices and a combination of scandals have eroded support for Mitsotakis’s government, now in its seventh year in power.
Chief among them are a farm subsidy scandal investigated by the EU, and a wiretapping scandal in which cabinet members, journalists and the head of the opposition, socialist leader Nikos Androulakis, were targeted.
There is also widespread anger about the slow investigation of Greece’s worst train disaster that claimed 57 lives in 2023, which took three years to get to a trial.
Αn Alco poll last week showed nearly 80 percent of Greeks believe laws are only “selectively” applied in the country, and nearly 50 percent said their vote would be influenced by rule of law issues.
Mitsotakis remains ahead in opinion polls.
Βut the political landscape has fragmented with as many as three new political parties likely to emerge in a challenge to his authority.
In addition to Tsipras’s formation, former conservative prime minister Antonis Samaras, a long-term critic of Mitsotakis who was kicked out of New Democracy in 2024, is also strongly rumoured to be planning a challenge