Between 1956 and 1981 it was at "cold war" with the Communist Party of the Netherlands as many former communists had joined the PSP's ranks. The PSP was highly critical of the CPN's Stalinist course. After 1981 the CPN, which had destalinized and PSP, began to cooperate more closely. The Christian left Political Party of Radicals and the Evangelical People's Party were also dismissed by the PSP as too supportive of the PvdA and too moderate on important issues. After 1981 the PPR broke its links with the PvdA and became more oriented toward PSP and CPN. In the 1980s the four parties began to cooperate in municipal and European elections, because fewer seats can be won there. In 1989 this intensive cooperation led to the formation of a new party, the GreenLeft.