After the Continuation War, the SKP dominated the Finnish People's Democratic League, which was founded in 1944 as an umbrella organization of the radical left.

[3] Internally, SKP was divided, with a Eurocommunist mainstream and a hardline pro-Moscow minority, called the Taistoists after their leader, Taisto Sinisalo.

The word "taisto" also means "battle" or "fight"; the double connotation made this slur, originally launched by the largest Finnish newspaper Helsingin Sanomat, stick.

Soviet threats to withdraw support were the main reason why the majority did not expel the Taistoists from the party leadership or membership.

While a de facto Eurocommunist majority held sway, the Taistoist minority decisively stood by the Soviet Union and the Brezhnev doctrine.

[5] The most hardline leader of the party, Markus Kainulainen, led a group that even opposed Soviet policies after the Perestroika had begun.

The dissolution of the Soviet Union in the early 1990s led to ideological conflicts: bitter internal disputes plagued the party.