Antonis Tritsis was a founding member of Panhellenic Socialist Movement (PASOK).
However, he was expelled by Andreas Papandreou for voting against the party regarding the PASOK's corruption in the Koskotas scandal.
[2] In the 1989 June elections, the Greek Radical Movement party received 4,162 votes and gained 0.1%.
[3] The following year, in the local elections of 1990, Antonis Tritsis decided to run for the Municipality of Athens.
On October 14, 1990, Tritsis elected Mayor of Athens as the leader of a coalition between New Democracy and the Greek Radical Movement.